Battery module and vehicle having the same

Abstract

The invention relates to a battery module and a vehicle having the same. In order to provide a battery module having a bus bar capable of coping with a large current, the present invention proposes a battery module comprising a plurality of battery cells having electrode terminals (2), and a bus bar that connects the electrode terminals (2) of adjacent battery cells to each other in a state in which the plurality of battery cells are stacked, the bus bars include a first bus bar having a first thickness and a second bus bar having a second thickness thicker than the first thickness, the first bus bar being respectively connected to the electrode terminals (2) of adjacent battery cells, and the second bus bar being not in contact with the electrode terminals (2) of the battery cells.

Description

[0001] The present application is a divisional application of an application with an application date of November 16, 2018, an application number of 201880092079.1 (PCT / JP2018 / 042374), and an invention name of “Battery module, vehicle having the battery module, and bus bar”. Technical Field

[0002] The present invention relates to a battery module and a vehicle having the battery module. Background Art

[0003] Battery modules are used in power supply devices for driving vehicles, power supply devices for storing electricity, etc. Such battery modules are preferably configured to be able to output a large current and have a plurality of battery cells connected in series or in parallel that can be charged and discharged. In addition, in recent years, it is desired to have a higher capacity of battery modules, and it is particularly important to cope with the parallel connection of many battery cells.

[0004] As a battery module having a plurality of battery cells connected in parallel, a battery module described in the following patent document is known. The battery module described in the following patent document has a plurality of battery cells, a plurality of conductive members connected to output terminals of the respective battery cells, and a bus bar connecting the plurality of battery cells in parallel via the plurality of conductive members.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2016-213026 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] The above-mentioned battery module requires fixing a plurality of conductive members connected to electrode terminals of each battery cell to one bus bar. If the relative positions of the bus bar and the plurality of conductive members are offset, the conductive members cannot be fixed to the bus bar.

[0010] The present invention has been made in view of the above background, and one object of the present invention is to provide a technology capable of improving assembly workability of a battery module having a plurality of battery cells connected in parallel.

[0011] Solutions for solving problems

[0012] A battery module according to one aspect of the present invention includes a plurality of battery cells having electrode terminals, and a bus bar that connects the electrode terminals of adjacent battery cells to each other in a state where the plurality of battery cells are stacked. The bus bar includes a first bus bar having a first thickness and a second bus bar having a second thickness thicker than the first thickness, the first bus bar being connected to each electrode terminal of the adjacent battery cells, respectively, and the second bus bar not being in contact with the electrode terminals of the battery cells.

[0013] In addition, a busbar according to one aspect of the present invention connects the electrode terminals of adjacent battery cells to each other in a state where a plurality of battery cells having electrode terminals are stacked. The busbar includes a first busbar having a first thickness and a second busbar having a second thickness thicker than the first thickness. The first busbar has a terminal connection portion for connecting to each electrode terminal of an adjacent battery cell, respectively, and a first flat portion for contacting the second busbar. The second busbar has a second flat portion in contact with the first flat portion.

[0014] Effects of the Invention

[0015] According to the above configuration, the second bus bar is connected to the first bus bar that connects the adjacent battery cells, so that the plurality of battery cells can be connected in parallel, thereby improving assembly workability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic perspective view of a battery module according to Embodiment 1 of the present invention.

[0017] Figure 2 yes Figure 1 An exploded perspective view of the battery module is shown.

[0018] Figure 3 It means from Figure 2 The battery module shown is an exploded perspective view in which the bus bar holder is omitted.

[0019] Figure 4 This is an enlarged perspective view showing the connection structure of a battery cell and a bus bar.

[0020] Figure 5 This is a perspective view of the bus bar according to the first embodiment.

[0021] Figure 6 yes Figure 5 Exploded perspective view of the bus bar.

[0022] Figure 7 yes Figure 1 Cross-sectional view at line VII-VII.

[0023] Figure 8This is a perspective view of a bus bar according to the second embodiment.

[0024] Fig. 9 yes Figure 8 Exploded perspective view of the bus bar.

[0025] Fig.10 It is an exploded perspective view showing a bus bar according to a modified example.

[0026] Fig.11 It is an exploded perspective view showing a bus bar according to a modified example.

[0027] Fig.12 It is an exploded perspective view showing a bus bar according to a modified example.

[0028] Fig.13 It is an exploded perspective view showing a bus bar according to a modified example.

[0029] Fig.14 This is a block diagram showing an example in which a battery module is mounted on a hybrid vehicle that runs using an engine and an electric motor.

[0030] Fig.15 This is a block diagram showing an example in which a battery module is mounted on an electric vehicle that travels only with an electric motor.

[0031] Fig.16 This is a block diagram showing an example of a battery module suitable for power storage.

[0032] Description of Reference Numerals

[0033] 100, 1000, battery module; 1, battery cell; 1A, first battery cell; 1B, second battery cell; 1X, terminal surface; 1a, outer shell can; 1b, sealing plate; 2, electrode terminal; 2a, protrusion; 2b, welding surface; 3, 3B, 3C, 3D, 3E, 3F, bus bar; 10, battery stack; 13, fixing component; 14, end plate; 15, fastening member; 16, insulating spacer; 17, end spacer; 18, insulating material; 81, building; 82, solar cell; 83, load; 85, DC / AC inverter; 91, vehicle body; 93, motor; 94, generator; 95, DC / AC inverter; 96, engine; 97, wheel; 98, charging plug; 310, 310A, 310B, 310C, 310D, 310E, 310F, the first a bus bar; 301, a bus bar holder; 311, a first terminal connection piece; 312, a first intermediate piece; 313, 313C, 313D, 313E, 313F, a first flat portion; 314, a second terminal connection piece; 315, a second intermediate piece; 316, 316C, 316D, 316E, 316F, a terminal connection portion; 317, a recess; 320, 320B, 320C, 320F 0D, 320E, 320F, second bus bar; 323, 323B, 323C, 323D, 323E, 323F, second flat portion; 324, protrusion; 330, opening portion; 331, recessed portion; 340, 340C, 340D, 340E, 340F, second end edge connecting portion; 341, connecting pin; 342, 342D, second bending portion; HV, vehicle; EV, vehicle. DETAILED DESCRIPTION

[0034] First, the process of conceiving an embodiment of the present invention is described. In a battery module having a structure in which a plurality of battery cells are connected in parallel by means of a bus bar, since current flows from the plurality of battery cells into the bus bar, the current flowing through the bus bar is relatively large compared to the case of a bus bar connected in series. When a large current flows through a bus bar with a large resistance, heat is generated, so as a bus bar for connecting a plurality of battery cells in parallel, a bus bar with a small resistance is preferably used.

[0035] On the other hand, in the case of a structure in which a busbar is used to connect multiple battery cells, the positional offset of each battery cell may sometimes become a problem. In particular, the battery cells may have dimensional deviations due to manufacturing tolerances, so it is preferable to use a flexible busbar so that the structure can absorb the displacement of the connected battery cells. In order to increase the flexibility of the busbar, it is effective to make the busbar thinner. However, since the resistance of a thin busbar is large, there is a problem of heat generation when a large current flows through it as described above. In this way, the reduction in the resistance of the busbar and the increase in flexibility are essentially contradictory and difficult to take into account at the same time.

[0036] In order to solve this problem, the present inventors have discovered that a bus bar that connects a plurality of battery cells in parallel has a portion where a smaller current flows than other portions, thereby completing the present invention.

[0037] In a battery module according to an embodiment of the present invention, the first bus bar has a terminal connection portion for connecting to an electrode terminal of a battery cell and a first flat portion in contact with the second bus bar, and the second bus bar has a second flat portion in contact with the first flat portion. According to the above structure, the second bus bar can be connected to the first bus bar connecting adjacent battery cells so that a plurality of battery cells can be connected in parallel, thereby improving assembly workability.

[0038] In addition, in a battery module of another embodiment of the present invention, the battery cell includes a first battery cell and a second battery cell that are adjacent and stacked, and the terminal connection portion includes a first intermediate sheet bent from the first flat portion, a first terminal connection sheet bent in a first direction via the first intermediate sheet, a second intermediate sheet bent from the first flat portion in a direction intersecting the first intermediate sheet, and a second terminal connection sheet bent in a second direction intersecting the first direction via the second intermediate sheet, the first terminal connection sheet is connected to the electrode terminal of the first battery cell, and the second terminal connection sheet is connected to the electrode terminal of the second battery cell. According to the above structure, the first bus bar can be deformed in multiple directions, and the flexibility of the bus bar can be further improved.

[0039] In addition, in a battery module of another embodiment of the present invention, the second flat portion of the second bus bar is formed into a straight line, and a plurality of first bus bars are fixed along the second flat portion. According to the above structure, the first bus bar and the second bus bar are easily positioned, and assembly workability can be further improved.

[0040] In a battery module according to another embodiment of the present invention, the first bus bars at both ends of the plurality of first bus bars are fixed in a posture where the second terminal connection pieces protrude outward. According to the above structure, deformation caused by expansion of the battery cell can be easily dealt with.

[0041] In a battery module according to another embodiment of the present invention, the second bus bar has a second edge connection portion formed by bending the edge for connection to an external connection portion. According to the above structure, the position of the second edge connection portion for connection to an external connection portion can be designed relatively freely.

[0042] In a battery module according to another embodiment of the present invention, the battery cells are connected in parallel. According to the above structure, even if a large amount of current flows through the bus bar due to the parallel connection, the thick second bus bar can ensure the current flow performance.

[0043] In addition, a vehicle according to another embodiment of the present invention includes the above-mentioned battery module, an electric motor for running that is supplied with electric power from the battery module, a vehicle body equipped with the battery module and the electric motor, and wheels driven by the electric motor to make the vehicle body run.

[0044] In addition, a bus bar of another embodiment of the present invention is a bus bar that connects the electrode terminals of adjacent battery cells to each other in a state where a plurality of battery cells having electrode terminals are stacked, and includes a first bus bar having a first thickness and a second bus bar having a second thickness thicker than the first thickness, the first bus bar having a terminal connecting portion for respectively connecting to the electrode terminals of adjacent battery cells and a first flat portion for contacting the second bus bar, and the second bus bar having a second flat portion in contact with the first flat portion.

[0045] Hereinafter, the embodiments of the present invention will be described based on the accompanying drawings. However, the embodiments shown below are examples for concretizing the technical ideas of the present invention, and the present invention is not particularly limited to the following embodiments. In addition, this specification is by no means intended to specifically limit the components shown in the claims to the components of the embodiments. In particular, the size, material, shape and relative configuration of the components described in the embodiments are not intended to limit the scope of the present invention to only this embodiment as long as there is no particularly specific record, but are only simple illustrative examples. In addition, in order to clearly explain, the size, positional relationship, etc. of the components shown in each figure are sometimes exaggerated. In addition, in the following description, the same name and figure mark are used to represent the same or substantially the same components and detailed description is appropriately omitted. In addition, the various elements constituting the present invention can be a form in which the same component constitutes multiple elements so that one component is used as multiple elements, or the function of realizing one component can be shared by multiple components on the contrary.

[0046] The battery module of the embodiment can be used for various purposes such as a power source installed in an electric vehicle such as a hybrid vehicle or an electric vehicle to supply power to the driving motor, a power source for storing power generated by natural energy such as solar power generation and wind power generation, or a power source for storing power late at night, and in particular, can be used as a power source suitable for large power and large current purposes.

[0047] [Implementation Method 1]

[0048] Figure 1 A perspective view showing a battery module 100 according to Embodiment 1 of the present invention is shown. Figure 2 shows an exploded perspective view of the battery module 100, Figure 3 Shows from Figure 2 The exploded perspective view of the bus bar holder 301 is omitted. Figure 4 An exploded perspective view showing the connection structure between the bus bar 3 and the electrode terminals is shown. Figure 1 and Figure 2 The battery module 100 shown has: a plurality of battery cells 1 having positive and negative electrode terminals 2; a bus bar 3 connected to the electrode terminals 2 of the plurality of battery cells 1 so as to connect the plurality of battery cells 1 in parallel and in series; and a bus bar holder 301 which holds the bus bar 3 and connects the plurality of battery cells 1 in parallel and in series with the aid of the bus bar 3. The battery cell 1 is a secondary battery capable of being charged and discharged. In the battery module 100, a plurality of battery cells 1 are connected in parallel to form a parallel battery pack, and a plurality of parallel battery packs are connected in series so as to connect a plurality of battery cells 1 in parallel and in series. Figure 1 and Figure 2 In the battery module 100 shown, a plurality of battery cells 1 are stacked to form a battery stack 10, and the battery stack 10 is fixed by a fixing member 13, thereby fixing the plurality of battery cells 1 in a stacked state. The fixing member 13 includes a pair of end plates 14 disposed on both end surfaces of the stacked battery cells 1, and a fastening member 15 whose ends are connected to the end plates 14 to fix the stacked battery cells 1 in a pressurized state.

[0049] (Battery cell 1)

[0050] The battery cell 1 is a square battery whose main surface as the wide surface is set to a quadrilateral shape, and its thickness is set to be thinner than the width. In addition, the battery cell 1 is a secondary battery that can be charged and discharged, and is set to be a lithium-ion secondary battery. However, the present invention does not specifically limit the battery cell to a square battery, nor does it specifically limit it to a lithium-ion secondary battery. The battery cell can also use all rechargeable batteries, such as non-aqueous electrolyte secondary batteries other than lithium-ion secondary batteries, nickel-metal hydride battery cells, etc.

[0051] The battery cell 1 is a cell obtained by housing an electrode body with stacked positive and negative electrode plates in an outer shell can 1a, filling it with electrolyte and sealing it airtightly. The outer shell can 1a is formed into a quadrangular cylinder with a closed bottom, and the opening above it is airtightly sealed by a sealing plate 1b of a metal plate. The outer shell can 1a is made by deep drawing a metal plate such as aluminum, aluminum alloy, etc. The sealing plate 1b is made of a metal plate such as aluminum, aluminum alloy, etc. in the same way as the outer shell can 1a. The sealing plate 1b is inserted into the opening of the outer shell can 1a and a laser beam is irradiated at the boundary between the outer periphery of the sealing plate 1b and the inner periphery of the outer shell can 1a, so that the sealing plate 1b is laser welded to the outer shell can 1a and airtightly fixed.

[0052] (Electrode terminal 2)

[0053] In the battery cell 1, the top surface, that is, the sealing plate 1b, serves as the terminal surface 1X, and positive and negative electrode terminals 2 are fixed to both ends of the terminal surface 1X. Figure 3 As shown, the positive and negative electrode terminals 2 are fixed to the sealing plate 1b by means of an insulating material 18 and are respectively connected to the built-in positive and negative electrode plates (not shown). The positive and negative electrode terminals 2 are provided with a welding surface 2b around the protrusion 2a. The welding surface 2b is a plane parallel to the surface of the sealing plate 1b, and a protrusion 2a is provided in the central part of the welding surface 2b. Figure 4 The protrusion 2a of the electrode terminal 2 is formed into a cylindrical shape. However, the protrusion does not necessarily have to be cylindrical, and although not shown in the figure, it may be formed into a polygonal column or an elliptical column.

[0054] The positive and negative electrode terminals 2 fixed to the sealing plate 1b of the battery cell 1 are positioned so that the positive electrode and the negative electrode are symmetrical. Thus, the battery cells 1 are stacked in a left-right flipped manner and the adjacent and close positive and negative electrode terminals 2 are connected by the bus bar 3, so that the adjacent battery cells 1 can be connected in series.

[0055] (Battery stack 10)

[0056] Multiple battery cells 1 are stacked in a stacking direction with the thickness of each battery cell 1 being the stacking direction to form a battery stack 10. The battery stack 10 is stacked with multiple battery cells 1 in a manner such that the terminal surfaces 1X provided with the positive and negative electrode terminals 2, i.e., the sealing plates 1b in the figure, are flush with each other.

[0057] In the battery stack 10, if Figure 3As shown, an insulating spacer 16 is sandwiched between the stacked battery cells 1. The insulating spacer 16 in the figure is made of an insulating material such as resin and is in a thin plate or sheet shape. The insulating spacer 16 shown in the figure is formed into a plate shape that is approximately equal in size to the opposite surface of the battery cell 1, and the insulating spacer 16 is stacked between the adjacent battery cells 1 to insulate the adjacent battery cells 1 from each other. In addition, as a spacer arranged between adjacent battery cells 1, a spacer having a shape that forms a flow path for cooling gas between the battery cell 1 and the spacer can also be used. In addition, the surface of the battery cell 1 can also be covered with an insulating material. For example, a shrink tube such as PET resin can be used to heat-weld the surface of the outer shell can other than the electrode portion of the battery cell. In this case, the insulating spacer 16 can also be omitted. In addition, in the battery module 100 of the embodiment, since a plurality of battery cells are connected in parallel and in series, an insulating spacer 16 is sandwiched between the battery cells connected in series. However, for the battery cells connected in parallel, since there is no voltage difference between adjacent outer shell cans, the insulating spacer between these battery cells can be omitted.

[0058] also, Figure 3 The battery module 100 shown in the figure has end plates 14 disposed on both end faces of the battery stack 10 via end face spacers 17. Figure 3 As shown, the end face spacer 17 is arranged between the battery stack 10 and the end plate 14 so as to insulate the end plate 14 from the battery stack 10. The end face spacer 17 is made of an insulating material such as resin and is in a relatively thin plate or sheet shape. The end face spacer 17 shown in the figure is set to a size and shape that can cover the entire opposite surface of the square battery cell 1, and is stacked between the end plate 14 and the battery cells 1 arranged at both ends of the battery stack 10.

[0059] In the battery stack 10, the positive and negative electrode terminals 2 of adjacent battery cells 1 are connected to a metal bus bar 3, and the plurality of battery cells 1 are connected in parallel and in series by means of the bus bar 3. In the battery stack 10, the plurality of battery cells 1 connected in parallel to form a parallel battery pack are stacked in such a manner that the positive and negative electrode terminals 2 provided at both ends of the terminal surface 1X are in the same left-right direction, and the plurality of battery cells 1 connected in series to form a parallel battery pack are stacked in such a manner that the positive and negative electrode terminals 2 provided at both ends of the terminal surface 1X are in opposite left-right directions. Here, Figure 3In the battery module 100 of the first embodiment shown, 12 battery cells 1 are stacked in the thickness direction to form a battery stack 10, 4 battery cells 1 are connected in parallel to form a parallel battery pack, and 3 parallel battery packs are connected in series to connect 12 battery cells 1 in a manner of 4 in parallel and 3 in series. Figure 3 In the battery stack 10 shown, the four battery cells 1 constituting the parallel battery group are stacked in such a manner that the positive and negative electrode terminals 2 are in the same direction from left to right, and three parallel battery groups formed by four battery cells 1 stacked in the same direction are stacked in such a manner that the positive and negative electrode terminals 2 are alternately in opposite directions from left to right. However, the present invention does not particularly limit the number of battery cells constituting the battery stack and their connection state. Including another embodiment described later, the number of battery cells constituting the battery stack and their connection state can be variously changed.

[0060] In the battery module 100 of the embodiment, in a battery stack 10 where a plurality of battery cells 1 are stacked on one another, electrode terminals 2 of adjacent battery cells 1 are connected to one another by bus bars 3 , thereby connecting the plurality of battery cells 1 in parallel and in series.

[0061] (Bus bar holder 301)

[0062] like Figure 1-2 As shown, the battery module 100 is provided with a bus bar holder 301 between the battery stack 10 and the bus bar 3, thereby making it possible to insulate the plurality of bus bars 3 from each other and to insulate the terminal surface of the battery cell from the bus bar 3, and to arrange the plurality of bus bars 3 at fixed positions on the upper surface of the battery stack 10. As such a bus bar holder 301, for example, the inner side of the holder body for arranging the plurality of bus bars 3 can be divided into a plurality of partitions to provide a structure having partition chambers for arranging the bus bars 3. The bus bar holder 301 is formed of an insulating material such as plastic, for example, and the plurality of bus bars 3 are arranged at fixed positions using a fitting structure, thereby making it possible to insulate the electrode terminals having a potential difference, and to arrange the plurality of bus bars 3 at fixed positions on the upper surface of the battery stack 10. In addition, in Figure 3 Hereinafter, in order to facilitate the identification of the connection state between the battery cells and the bus bars 3 , the bus bar holder 301 for arranging the plurality of bus bars 3 at fixed positions is omitted from illustration.

[0063] (Bus 3)

[0064] The metal plate is cut and processed to manufacture the bus bar 3 into a predetermined shape. The metal plate constituting the bus bar 3 can use a metal with low electrical resistance and light weight, such as an aluminum plate, a copper plate, or an alloy thereof. However, the metal plate of the bus bar 3 can also use other metals with low electrical resistance and light weight, or alloys of these metals.

[0065] In the present embodiment, the bus bar 3 for connecting the electrode terminals 2 of the plurality of battery cells 1 in a predetermined connection state is provided with a unique structure. Figure 3 to Figure 7 The detailed structure of the bus bar 3 will be described in detail. The bus bar 3 connects the opposing electrode terminals 2 of the battery cells 1 disposed adjacent to each other among the plurality of battery cells 1 stacked in a predetermined arrangement, thereby connecting the plurality of battery cells 1 in parallel and in series. Figure 4 The bus bar 3 shown is arranged on the upper surface of the battery stack 10 and faces the terminal surface 1X of the battery cells 1 , and connects the plurality of electrode terminals 2 arranged along the stacking direction of the plurality of battery cells 1 in a substantially linear manner on both sides of the battery stack 10 .

[0066] like Figure 5 , Figure 6 As shown, the bus bar 3 is formed by a first bus bar 310 having a first thickness and a second bus bar 320 having a second thickness thicker than the first thickness. Moreover, the first bus bar 310 side is set to be connected to each electrode terminal 2 of the adjacent battery cell 1, and the second bus bar 320 side is set not to contact the electrode terminal 2 of the battery cell 1. In this way, the deviation of the position of the electrode terminal 2 of the battery cell 1 is absorbed on the side of the first bus bar 310 which is thinner and easier to deform, thereby ensuring the followability and ease of assembly when the bus bar 3 is fixed to the battery cell 1. On the other hand, the second bus bar 320 side is formed to be thicker, thereby reducing the resistance and ensuring the large current conduction performance achieved by the connection of the battery cell 1.

[0067] On the other hand, the first bus bar 310 can be made thinner so that it can also have a temperature fuse function. That is, when a large current is passed, the first bus bar 310 is melted to improve safety. In this way, the bus bar 3 is divided into the first bus bar 310 and the second bus bar 320, so that the contradictory problems of the followability of the electrode terminal and the control of heat generation can be taken into account.

[0068] (First bus bar 310)

[0069] The first bus bar 310 has a terminal connection portion 316 for connection to the electrode terminal 2 of the battery cell 1 , and a first flat portion 313 in contact with the second flat portion 323 of the second bus bar 320 .

[0070] In addition, the terminal connection portion 316 of the first bus bar 310 includes a first intermediate piece 312 bent from the first flat portion 313, a first terminal connection piece 311 bent in a first direction via the first intermediate piece 312, a second intermediate piece 315 bent from the first flat portion 313 in a direction intersecting the first intermediate piece 312, and a second terminal connection piece 314 bent in a second direction intersecting the first direction via the second intermediate piece 315. Figure 4 As shown, the first terminal connecting piece 311 is connected to the electrode terminal 2 of one battery cell 1 , and the second terminal connecting piece 314 is connected to the electrode terminal 2 of the battery cell 1 adjacent to the battery cell 1 .

[0071] In this way, the positional displacement of the electrode terminals can be dealt with. Depending on the use environment of the battery module, the relative positional relationship between the electrode terminals may sometimes be offset. For example, the battery cell will expand due to charging and discharging, so when multiple battery cells are stacked, the more the number of stacking is, the greater the amount of movement of the electrode terminal in the stacking direction. In addition, in a battery module for vehicle use, the stacked battery cells will be offset due to vibration and impact, resulting in the relative positional relationship between the electrode terminals being offset, thereby applying a load to the busbar connecting them. Therefore, the busbar is provided with a mechanism for absorbing such positional displacement. Specifically, the first terminal connecting piece 311 and the second terminal connecting piece 314 are bent in directions orthogonal to each other via the first intermediate piece 312 and the second intermediate piece 315, respectively, thereby ensuring the flexibility achieved by the bending. In addition, even if the first busbar 310 is made of a thinner metal, it can also be easily deformed. In this way, the first busbar 310 is given flexibility that can follow the displacement of the electrode position, thereby improving the reliability of the connection between the busbar 3 and the electrode terminal 2. In addition, ease of assembly during the battery module assembly operation can be ensured.

[0072] The first bus bar 310 is used to connect Figure 4 This situation is explained by taking the example of each electrode terminal 2 of the adjacent and stacked first battery cell 1A and second battery cell 1B as shown. In this example, the first terminal connecting piece 311 is welded to the electrode terminal 2 of the first battery cell 1A and the second terminal connecting piece 314 is welded to the electrode terminal 2 of the second battery cell 1B. In this state, when the first battery cell 1A and the second battery cell 1B are displaced in the X direction, the first terminal connecting piece 311 moves accordingly. The first terminal connecting piece 311 is arranged with the aid of the first flat portion 313 and the first intermediate piece 312 and can be bent and deformed. That is, the bending is performed at the bending portion between the first intermediate piece 312 and the first terminal connecting piece 311 and the bending portion between the first intermediate piece 312 and the first flat portion 313, so that it can be deformed. Figure 4 Move slightly in the direction indicated by arrow X.

[0073] On the other hand, when the electrode terminal 2 moves relative to the Y direction, the second terminal connecting piece 314 absorbs the movement. The second terminal connecting piece 314 is bent by the second intermediate piece 315 in a direction substantially perpendicular to the first intermediate piece 312. As a result, the electrode terminal 2 can move relative to the first intermediate piece 312. Figure 4 Move slightly in the direction indicated by arrow Y.

[0074] Furthermore, even when the electrode terminal 2 moves relatively in the Z direction, the first intermediate sheet 312 and the second intermediate sheet 315 can be bent and tilted to absorb the height difference, thereby being able to cope with the above. Figure 4 The relative displacement in the direction indicated by the arrow Z.

[0075] In this way, even if the position of the electrode terminal 2 of the battery cell 1 deviates, it can be absorbed by the deformation of the first bus bar 310, thereby alleviating the load generated at the mechanical connection point between the first bus bar 310 and the electrode terminal 2, and improving the stability and reliability of the connection.

[0076] The first terminal connection piece 311 and the second terminal connection piece 314 are provided with an opening 330. The opening 330 is formed in a circular shape. Figure 4 As shown, the opening 330 is welded to the electrode terminal 2 of the battery cell 1 by laser welding or the like. Figure 5 , Figure 6 As shown, the opening 330 is partially formed with a recess 331 in the circular shape. The recesses 331 are preferably respectively arranged at positions opposite to the center of the circular opening 330. This makes it easy to bend on a line passing through the center, and can increase the flexibility of the first terminal connecting piece 311 and the second terminal connecting piece 314, thereby improving the followability during deformation.

[0077] Preferably, the first bus bar 310 is formed of a material having excellent conductivity and flexibility. Here, it is made of a metal such as aluminum plate, copper, or nickel. In addition, the surface can be plated as needed. As for the type of plating, nickel or the like can be used.

[0078] (Second bus bar 320)

[0079] The second bus bar 320 is formed thicker than the first bus bar 310. The second bus bar 320 has a second flat portion 323 in contact with the first flat portion 313 of the first bus bar 310. By forming the second bus bar 320 thicker and increasing the cross-sectional area, the resistance is reduced, and heat generation can be suppressed even when a large current is passed.

[0080] In addition, the second flat portion 323 is extended in a plate shape, thereby making it easy to fix the plurality of first bus bars 310 along the length direction. In addition, a guide may be provided to facilitate positioning of the position where the first bus bar 310 is fixed to the second bus bar 320. As an example of a guide, Figure 6 In the embodiment, a protrusion 324 is formed on the second flat portion 323 of the second bus bar 320, and a recess 317 for receiving the protrusion 324 is formed on the first flat portion 313 of the first bus bar 310. In this way, the recess 317 is brought into contact with the protrusion 324, so that the first bus bar 310 can be fixed to a predetermined position of the second bus bar 320. In addition, it is preferable to form the recess 317 on both sides of the intersection. In this way, the first bus bar 310 can be prevented from being displaced in the direction of rotation.

[0081] The second bus bar 320 is formed of the same material as the first bus bar 310, thereby facilitating welding of the first bus bar 310 and the second bus bar 320. However, the second bus bar and the first bus bar may be formed of different materials. For example, the first bus bar may be changed to a metal material suitable for welding according to the material of the electrode terminal 2. In this way, it is easy to design according to the battery cell used.

[0082] The first bus bar 310 and the second bus bar 320 are fixed to each other. The first bus bar 310 and the second bus bar 320 are fixed to each other by using the first flat portion 313 of the first bus bar 310 and the second flat portion 323 of the second bus bar 320. The fixing can be performed by welding, mechanical connection such as screw connection by bolts, riveting, etc.

[0083] In addition, it is preferred that the fixing position between the first flat portion 313 of the first bus bar 310 and the second flat portion 323 of the second bus bar 320 is a position that does not overlap with the connection position where the first terminal connecting piece 311 and the second terminal connecting piece 314 are connected to each electrode terminal 2. Figure 4 Stereoscopic image, Figure 7 As shown in the cross-sectional view of , the first flat portion 313 and the second flat portion 323 are arranged to overlap at a position outside the row of electrode terminals 2 of each stacked battery cell 1. In this way, when welding the electrode terminal 2 of the battery cell 1 and the first bus bar 310, the second flat portion 323 can be excluded from the upper part of the welding part to ensure an open space, and the advantage of being able to smoothly perform laser welding without being disturbed by the second flat portion 323 can be obtained. For example, after welding the first bus bar 310 and the second bus bar 320, the bus bar can be assembled and welded to the battery stack 10.

[0084] The second bus bar 320 can fix the plurality of first bus bars 310. Figure 5 as well as Figure 6 In the example of FIG. 1 , four first bus bars 310 are fixed to the second bus bar 320. Figure 8 , Fig. 9 In the example shown, two first bus bars 310 are fixed to the second bus bar 320. In this way, the number of first bus bars is determined according to the number of battery cells 1 to be connected. In addition, the length of the second flat portion of the second bus bar can be adjusted according to the number of first bus bars. In other words, different numbers of first bus bars can be fixed by changing the second bus bar, thereby being able to cope with the connection of various numbers of battery cells 1.

[0085] When a plurality of first bus bars 310 are arranged and fixed to the second flat portion 323 of the second bus bar 320, the first bus bar 310 located at the edge of the second flat portion 323 is fixed in a posture where the second terminal connection piece 314 is located outside. In this case, a component obtained by flipping the outer shape of the first bus bar 310 left and right is prepared in advance. Figure 6 In the embodiment, the first bus bar 310A and the first bus bar 310B are set to a left-right flipped shape. This configuration can especially cope with the situation where the battery cells located at the edge of the stacked battery cells are prone to expand to the left and right due to expansion. In other words, the first bus bar is fixed in a posture where the second terminal connecting piece protrudes to both sides, so that it becomes a posture that is easy to deform in the stacking direction of the battery cells, thereby obtaining the advantage of being able to stably maintain the connection state of the bus bar and the electrode terminal even when such a battery cell expands.

[0086] [Implementation Method 2]

[0087] The above description has been made of an example in which the second bus bar is formed as a whole in a flat plate shape. However, the present invention is not limited to this shape, and the second bus bar may also have a second end edge connection portion for connecting to an external connection portion. Such an example is shown as a bus bar of Embodiment 2. Figure 8 Stereoscopic images and Fig. 9 In these figures, the first bus bar 310 is the same as that in the above-mentioned first embodiment, and detailed description thereof is omitted.

[0088] The bus bar 3B of the second embodiment is also similar to the first embodiment, and the second bus bar 320B is provided with a second flat portion 323B. On the other hand, the second bus bar 320B of the second embodiment is provided with a second edge connecting portion 340 at the edge. Figure 8 , Fig. 9In the example shown, the second flat portion 323B of the second bus bar 320B is bent to provide a second end edge connection portion 340. In this way, the bus bar can be easily electrically connected to the outside. It is particularly suitable for drawing out large currents. It is preferred to set the bus bar on the end surface of the battery stack so that it can be used to draw out the total potential of multiple battery cells.

[0089] It is preferred that the connection pin 341 protrudes from the second end edge connection part 340. Thus, connection with an external terminal can be easily performed. The connection pin 341 can preferably utilize a stud bolt. In addition, the connection pin 341 is joined to the second end edge connection part 340 by riveting, press fitting, bonding, etc. Therefore, it is preferred that a hole for the connection pin 341 to be press-fitted is formed in the second end edge connection part 340.

[0090] In addition, the second end edge connection portion 340 preferably has a second bent portion 342 formed between the second end edge connection portion 340 and the second flat portion 323B, thereby providing the connection pin 341 with flexibility that allows it to be slightly displaced. Figure 8 , Fig. 9 In the example shown, the second bent portion 342 is provided to be continuous from the second end edge connection portion 340 and inclined downward. Thus, even if the connection pin 341 is relatively displaced, the second bent portion 342 can absorb such a displacement and maintain the stability of the connection. Figure 8 In the example of , the second end edge connecting portion 340 is provided as a surface lower than the second flat portion 323B.

[0091] [Modifications]

[0092] In the above example, an example of fixing a plurality of first bus bars to a second bus bar is described. However, the present invention does not limit the number of first bus bars to a plurality, and it is also possible to fix a single first bus bar to a second bus bar. Figure 5 In the example of FIG. 1 , an example is described in which two terminal connection pieces, the first terminal connection piece 311 and the second terminal connection piece 314, are provided on a first bus bar 310, but more than three terminal connection pieces may be provided. In this case, it is preferred that the distance from the battery cell 1 to the bus bar is equal for each terminal connection piece. Thus, even if the number of battery cells 1 connected in parallel changes, the path does not change.

[0093] As a modification, Fig.10 , Fig.11 , Fig.12 , Fig.13Examples are shown in which the number of terminal connection pieces is set to three or more. In the busbars 3C, 3D, 3E, and 3F shown in these examples, as first busbars 310C, 310D, 310E, and 310F, first flat portions 313C, 313D, 313E, and 313F and terminal connection portions 316C, 316D, 316E, and 316F are respectively bent in advance and four terminal connection pieces are provided as terminal connection portions 316C, 316D, 316E, and 316F. The first busbars 310C, 310D, 310E, and 310F are fixed to the second busbars 320C, 320D, 320E, and 320F by welding or screwing. Figure 10 to Figure 12 An example in which the first bus bars 310C, 310D, 310E and the second bus bars 320C, 320D, 320E are fixed by welding is shown. Fig.13 The example in which the first bus bar 310F and the second bus bar 320F are fixed by screwing is shown. In this way, by integrating a plurality of bus bars, the positioning work can be simplified when welding the bus bars, compared with the case where the bus bars are provided independently.

[0094] Alternatively, the terminal connection portions 316C, 316D, 316E, and 316F may be partially subjected to drawing or the like so as to be able to withstand slight deformation of the electrode terminals.

[0095] In addition, on the second bus bar 320C, 320D, 320E, 320F side, the second edge connection portion 340C, 340D, 340E, 340F is provided at one edge (right side in the figure) of the second flat portion 323C, 323D, 323E, 323F. The second edge connection portion 340C, 340D, 340E, 340F can be in various forms. For example, Fig.10 , Fig.11 As shown, the second flat portions 323C and 323D are set in a vertical position and the end edges are formed into an L shape so as to protrude downward, and the L-shaped protruding portion is bent in a horizontal position to form a connecting pin 341. Fig.11 In the example of FIG. 3 , a second bent portion 342D is provided by inclining the end of the second flat portion 323D, thereby enabling this portion to have a function of absorbing the displacement of the connecting pin 341 .

[0096] In addition, Fig.12 , Fig.13 In the example, the second flat portions 323E and 323F are set in a horizontal position and the connecting pin 341 is made to stand upright from the upper surface. Fig.12In the example, the edge of the second flat portion 323E is formed into an L-shape in a plan view, so that the position of the connecting pin 341 is offset from the main surface of the second flat portion 323E.

[0097] When the first bus bar and the second bus bar of such a form are used, they can be divided into thicker bus bars and thinner bus bars in the same manner, thereby being able to cope with the followability and heat generation properties with respect to the electrode terminal 2 .

[0098] The above battery modules can be used as a vehicle-mounted power source. As a vehicle equipped with the battery module, a hybrid vehicle that uses both an engine and an electric motor to run, a plug-in hybrid vehicle, or an electric vehicle that only uses an electric motor to run can be used, and the above battery modules are used as the power source of the above vehicles. In addition, an example of a large-capacity, high-output battery module 1000 constructed to obtain power to drive the vehicle is described, and a plurality of the above battery modules are connected in series and in parallel and a necessary control circuit is added to constitute the battery module 1000.

[0099] (Battery modules for hybrid vehicles)

[0100] Fig.14 An example of a hybrid vehicle equipped with a battery module that is driven by both an engine and an electric motor is shown. The vehicle HV equipped with a battery module shown in the figure has a vehicle body 91, an engine 96 that drives the vehicle body 91, and an electric motor 93 for driving, wheels 97 driven by the engine 96 and the electric motor 93 for driving, a battery module 1000 that supplies power to the electric motor 93, and a generator 94 that charges the batteries of the battery module 1000. The battery module 1000 is connected to the electric motor 93 and the generator 94 by means of a DC / AC inverter 95. The batteries of the battery module 1000 are charged and discharged, and the vehicle HV is driven by both the electric motor 93 and the engine 96. The electric motor 93 is driven in an area where the engine efficiency is low, such as when accelerating or driving at a low speed, to drive the vehicle. Electric power is supplied from the battery module 1000 to the electric motor 93 to drive it. The generator 94 is driven by the engine 96 or by regenerative braking when the vehicle is braked, thereby charging the batteries of the battery module 1000. In addition, as Fig.14 As shown, the vehicle HV may also include a charging plug 98 for charging the power module 1000. The battery module 1000 can be charged by connecting the charging plug 98 to an external power source.

[0101] (Battery modules for electric vehicles)

[0102] in addition, Fig.15An example of an electric vehicle that is driven only by an electric motor and equipped with a battery module is shown. The vehicle EV equipped with a battery module shown in this figure has a vehicle body 91, a motor 93 for driving the vehicle body 91, wheels 97 driven by the motor 93, a battery module 1000 that supplies power to the motor 93, and a generator 94 that charges the battery of the battery module 1000. The battery module 100 is connected to the motor 93 and the generator 94 by means of a DC / AC inverter 95. Power is supplied from the battery module 1000 to the motor 93 to drive it. The generator 94 is driven by the energy when the vehicle EV is regeneratively braked, thereby charging the battery of the battery module 1000. In addition, the vehicle EV has a charging plug 98, which is connected to an external power supply so that the battery module 1000 can be charged.

[0103] (Electricity Storage System)

[0104] The present invention does not limit the use of the battery module to a power source for a motor that drives a vehicle. The battery module of the embodiment can also be used as a power source for a power storage system that charges and stores electricity in a battery using electricity generated by solar power generation, wind power generation, etc. Fig.16 The power storage system shown in the figure charges the battery of the battery module 1000 by using solar cells and stores electricity. As shown in the figure, the power storage system shown in this figure charges the battery of the battery module 100 by using the power generated by the solar cell 82 arranged on the roof or roof of a building 81 such as a house or factory. In addition, the power storage system supplies the power stored in the battery module 100 to the load 83 via the DC / AC inverter 85.

[0105] In addition, although not shown, the battery module can also be used as a power source for a power storage system that uses late-night electricity to charge and store electricity in the battery. In the battery module that uses late-night electricity for charging, the surplus electricity of the power station, i.e., late-night electricity, is used for charging, and the electricity is output during the day when the power load is large, so that the peak power during the day can be limited to a small value. In addition, the battery module can also be used as a power source that uses both the output of the solar cell and the late-night electricity for charging. The battery module can effectively use both the electricity generated by the solar cell and the late-night electricity, and can store electricity efficiently while taking into account the weather and power consumption.

[0106] The power storage system as described above can be preferably used for backup battery modules that can be mounted on a bracket of a computer server, backup battery modules for wireless base stations of mobile phones, etc., power supplies for home or factory power storage, power supplies for street lights, etc., power storage devices combined with solar cells, backup power supplies for traffic lights, traffic displays for roads, etc.

[0107] Industrial Applicability

[0108] The cooling method, cooling program, computer-readable recording medium, and stored device, battery module, and vehicle having the battery module of the present invention can be preferably used as a power source for large current used for the power source of the motor that drives electric vehicles such as hybrid vehicles, fuel cell vehicles, electric vehicles, and electric motorcycles. For example, battery modules of plug-in hybrid electric vehicles, hybrid electric vehicles, electric vehicles, etc. that can switch between EV driving mode and HEV driving mode can be cited. In addition, it can also be appropriately used for backup battery modules that can be mounted on the bracket of a computer server, backup battery modules for wireless base stations such as mobile phones, power storage power supplies for home and factory use, power storage devices composed of power storage devices such as power supplies for street lamps and solar cells, and backup power supplies for traffic lights, etc.

Claims

1. A battery module comprising a plurality of battery cells having electrode terminals, and a bus bar connecting the electrode terminals of adjacent battery cells to each other in a state where the plurality of battery cells are stacked, wherein: The bus bar has: a first bus bar having a first thickness; as well as a second bus bar having a second thickness thicker than the first thickness, The first bus bar is connected to each electrode terminal of the adjacent battery cells, and The second bus bar does not contact the electrode terminal of the battery cell, The first bus bar has: a terminal connection portion for connecting to an electrode terminal of a battery cell; and a first flat portion in contact with the second bus bar, The second bus bar has a second flat portion in contact with the first flat portion, The battery cells include a first battery cell and a second battery cell that are adjacent and stacked, The terminal connection portion has: A first terminal connecting piece connected to an electrode terminal of the first battery cell; and A second terminal connecting piece connected to the electrode terminal of the second battery cell, The first battery cell and the second battery cell are connected in parallel via a contact portion between the first flat portion and the second flat portion.

2. The battery module according to claim 1, wherein: In the battery module, a plurality of battery cells are connected in parallel to form a parallel battery group, and a plurality of the parallel battery groups are connected in series. The plurality of parallel battery groups are connected in series via the second flat portion.

3. The battery module according to claim 1, wherein: The second flat portion of the second bus bar is formed in a straight line shape. A plurality of the first bus bars are fixed along the second flat portion. The battery cells connected to the first bus bars are connected in parallel or in series via the second flat portion.

4. The battery module according to claim 1, wherein: In the battery module, a plurality of battery cells are stacked in such a manner that the terminal surfaces provided with the positive and negative electrode terminals are in the same plane, and the positive and negative electrode terminals of each battery cell are arranged in a width direction orthogonal to the stacking direction of the battery cells. The bus bars are provided on one side and the other side in the width direction, respectively.

5. The battery module according to claim 4, wherein: A plurality of the bus bars are provided on one side and the other side in the width direction, respectively. The second bus bars included in the plurality of bus bars provided on one side in the width direction and the second bus bars included in the plurality of bus bars provided on the other side in the width direction are alternately arranged in the stacking direction.

6. The battery module according to claim 5, wherein: The terminal connection portion has: A first intermediate sheet bent from the first flat portion; The first terminal connecting piece is bent toward a first direction via the first intermediate piece; A second intermediate sheet bent from the first flat portion to a direction intersecting the first intermediate sheet; and The second terminal connecting piece is bent in a second direction intersecting the first direction via the second intermediate piece. The second flat portion of the second bus bar is formed in a straight line shape. A plurality of the first bus bars are respectively fixed along the second flat portion of each of the bus bars, Among the plurality of first bus bars fixed to the second flat portions, the first bus bars located at both ends are fixed in a posture in which the second terminal connection pieces protrude outward.

7. The battery module according to claim 1, wherein: In a width direction perpendicular to the stacking direction of the battery cells, a fixing position between the first flat portion and the second flat portion is located outside a connection position where the first terminal connecting piece and the second terminal connecting piece are connected to the electrode terminals.

8. The battery module according to claim 1, wherein: The first bus bar and the second bus bar are formed of the same material.

9. The battery module according to claim 1, wherein: The first terminal connecting piece and the second terminal connecting piece are provided with openings for welding to electrode terminals of the battery cells, and the openings are provided with recessed portions at locations facing the center of the circular openings.

10. The battery module according to claim 1, wherein: A protrusion is formed on the second flat portion, and a recessed portion for receiving the protrusion is formed on the first flat portion.

11. The battery module according to claim 10, wherein: The recessed portion is formed on both sides of the intersection of the first flat portion.

12. The battery module according to claim 1, wherein: The second flat portion has no hole portion at a location in contact with the first flat portion.

13. The battery module according to claim 1, wherein: The second bus bar has a second end edge connection portion formed by bending an end edge and for connecting to an external connection portion.

14. A vehicle comprising the battery module according to any one of claims 1 to 13, wherein: The vehicle includes the battery module, a motor for traveling to which electric power is supplied from the battery module, a vehicle body on which the battery module and the motor are mounted, and wheels driven by the motor to cause the vehicle body to travel.

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