JP5322703B2 - Battery and battery pack - Google Patents

Description

  The present invention relates to a battery and an assembled battery. Specifically, the present invention relates to a battery (unit cell) and an assembled battery that are electrically connected via a bus bar.

  Lithium-ion batteries, nickel-metal hydride batteries and other secondary batteries or capacitors and other storage elements are used as unit cells, and a battery pack formed by connecting a plurality of unit cells in series is used as a power source for vehicle mounting, It is becoming increasingly important as a power source for personal computers and mobile terminals. In particular, an assembled battery in which a plurality of lithium-ion batteries that are lightweight and have a high energy density are connected in series as single cells is expected to be preferably used as a high-output power source for mounting on vehicles.

  In an assembled battery composed of a plurality of unit cells of this type, a structure in which adjacent unit cells are connected to each other by a bus bar is known. For example, Patent Document 1 discloses a configuration in which unit cells are connected to each other by a bus bar. Here, the bus bar is attached to the bolt portion of the bolt-type electrode terminal, and the bus bar is fixed so as not to be detached by tightening the nut from above the bus bar. Patent document 2 is mentioned as another prior art regarding the connection of this kind of bus bar and an electrode terminal.

JP 2007-188787 A JP 2003-331816 A

  By the way, as a constituent material of an electrode terminal, since it is necessary to use a material with good tolerance with respect to electrolyte, generally the metal material with high tolerance with respect to organic solvents, such as aluminum and copper, is employ | adopted. However, since the electrode terminal made of aluminum or copper has a low physical strength, the bolt portion of the electrode terminal is easily damaged if the torque when tightened with a nut is too large. That is, there is a problem that a high torque cannot be applied when the nut is fastened. If the torque at the time of tightening the nut is not appropriate, the nut loosens due to vibration applied to the battery or the like, which may cause inconvenience in the connection between the bus bar and the electrode terminal. For example, when the nut is loosened, the contact state between the bus bar and the electrode terminal becomes unstable, which causes a problem that the conductivity between the bus bar and the electrode terminal is deteriorated. In particular, assembled batteries mounted on automobiles and the like are premised on use in a state where vibrations are generated, so a connection structure between bus bars and electrode terminals is required that does not cause inconvenience due to vibrations applied to the batteries. .

  The inventor of the present application attempted to solve the problems related to the connection between the bus bar and the electrode terminal described above, not in the extension line of the prior art, but in a new direction. This invention is made | formed in view of this point, The main objective is to propose the novel structure for fixing a bus bar to an electrode terminal (connection).

  The assembled battery provided by the present invention is an assembled battery configured by electrically connecting a plurality of unit cells.

  The assembled battery according to the present invention includes a plurality of unit cells each including a battery case that houses an electrode body and electrode terminals that protrude from the outer surface of the battery case. In the plurality of unit cells, one electrode terminal and the other electrode terminal are connected to each other through a bus bar between adjacent unit cells. Here, the bus bar is a metal member having a plate-like main body portion connecting the electrode terminals, and constitutes a terminal insertion hole for inserting the electrode terminal and at least a part of a peripheral edge of the terminal insertion hole. And a claw portion formed so as to be inclined from the main body portion of the bus bar toward the tip end of the electrode terminal or the battery case. And the said bus bar is being fixed to the said electrode terminal by the said nail | claw part being crimped with respect to the electrode terminal inserted in the said terminal insertion hole, It is characterized by the above-mentioned.

  Here, “clamping” the claw part with respect to the electrode terminal (or “clamping the electrode terminal with respect to the claw part”) means that a mechanical external force is applied to at least one of the claw part and the electrode terminal. This means that at least a part of the claw part and / or the electrode terminal is deformed (collapsed) and the claw part and the electrode terminal are fixed to each other.

  In the present specification, the “single cell” is a term indicating individual storage elements that can be electrically connected to each other in order to constitute an assembled battery. Unless specifically limited, batteries and capacitors ( Physical battery). The “secondary battery” generally refers to a battery that can be repeatedly charged, and includes a so-called storage battery such as a lithium ion battery, a nickel metal hydride battery, and an electric double layer capacitor. The electric storage element constituting the lithium ion battery is a typical example included in the “unit cell” referred to herein, and the lithium ion battery module including a plurality of such unit cells is disclosed in the “assembled battery” Is a typical example.

  Moreover, this invention provides a battery provided with the battery case which accommodates an electrode body, and the electrode terminal protruded on the outer surface of the said battery case.

  Such a battery is connected to the electrode terminal, and is provided with a cell adjacent to the electrode terminal and a terminal outside the battery (for example, when an assembled battery including a plurality of the batteries of the present invention is provided as a cell). A bus bar that connects to the electrode terminal. The bus bar is a metal member having a plate-shaped main body, and includes a terminal insertion hole into which the electrode terminal is inserted, and a claw portion that forms at least a part of a peripheral edge of the terminal insertion hole. And a claw portion formed so as to incline toward the tip end of the electrode terminal or the battery case. And the said bus bar is being fixed to the said electrode terminal by the said nail | claw part being crimped with respect to the electrode terminal inserted in the said terminal insertion hole, It is characterized by the above-mentioned.

  In the assembled battery or battery according to the present invention, for example, as a bus bar (metal connecting member) that electrically connects one electrode terminal and the other electrode terminal between single cells, a flat main body portion, a terminal insertion hole, And a claw portion formed at a part of the periphery of the terminal insertion hole, and the claw portion extends from the main body portion toward the tip of the electrode terminal (ie, away from the battery case) or in the battery case direction (ie, battery). A bus bar characterized by being bent so as to stand up from the main body so as to be inclined in a direction approaching the case) is used. That is, by using the bus bar having such a configuration, the claw portion which is an area portion formed so as to rise from the main body portion as the bent portion can be effectively used for caulking and fixing.

  Therefore, in the assembled battery or battery according to the present invention, the claw portion of the bus bar is caulked against the electrode terminal (that is, as described above, at least a part of the claw portion and / or the electrode terminal is deformed (collapsed) by a mechanical external force. Then, the bus bar and the electrode terminal can be securely fixed by a simple method of fixing the claw portion and the electrode terminal to each other. In addition, the connection interface between the bus bar and the electrode terminal is stable (because the screw does not loosen due to vibration) compared to the conventional structure in which the bus bar is screwed. Can keep. Furthermore, nutlessness is possible, and the number of parts and cost can be reduced. In addition, when the bus bar claw portion is caulked against the electrode terminal, the oxide film formed on the surface of the electrode terminal (typically an oxide film formed by natural oxidation of the electrode terminal) is scraped off. And the electrode terminal are in contact with each other. Therefore, the energization resistance between the bus bar and the electrode terminal is lowered, and the energization property between the bus bar and the electrode terminal is improved. Therefore, according to the present invention, it is possible to provide an assembled battery or a battery having a low external connection resistance.

  In a preferred aspect of the assembled battery or battery disclosed herein, the claw portion extends from the bus bar main body portion formed so as to constitute the entire periphery of the terminal insertion hole to the tip direction or the battery case. An annular claw that rises in a direction, and the annular claw is caulked over the entire circumference of the electrode terminal. By using the bus bar having such a structure, the annular claw portion can be caulked over the entire circumference of the electrode terminal, the connection strength (caulking strength) between the bus bar and the electrode terminal is further increased, and the bent portion is The claw part which is an area part formed so that it may stand up from a main-body part can be used more effectively for caulking fixation. In addition, since the annular claw portion is caulked along the circumferential direction of the electrode terminal, even if a force acts in the removal direction (the axial direction of the electrode terminal), a large resistance can be exhibited.

  In a preferred aspect of the assembled battery or battery disclosed herein, the annular claw portion is formed with a slit extending outward from the terminal insertion hole. According to such a configuration, the rigidity of the annular claw portion is lowered and is easily deformed. Therefore, it becomes easy to caulk the annular claw portion to the electrode terminal, and the assembling workability is improved.

  In a preferred embodiment of the assembled battery or battery disclosed herein, a press ring member is fitted to the electrode terminal inserted into the terminal insertion hole of the bus bar closer to the tip of the electrode terminal than the terminal insertion hole. Has been. And the said claw part interposed between this pressing ring member and a battery case is crimped with respect to the said electrode terminal by the said pressing ring member being pushed in the said battery case direction. According to such a configuration, the bus bar can be fixed simply by pushing the presser ring member, and the assembly workability is good. Therefore, construction of an assembled battery or the like can be performed quickly. Further, the bus bar can be fixed simply by pushing the press ring member, and a wide tooling space (a gap for inserting a tool such as a wrench) is not required around the electrode terminal. Therefore, even if it is a compact assembled battery or battery with a short distance between terminals, a bus bar can be fixed easily.

  In a preferred embodiment of the assembled battery or battery disclosed herein, the surface of the holding ring member facing the bus bar corresponds to the inclination of the claw portion from the bus bar main body portion to the electrode terminal tip direction. An inclined surface is formed. In this case, it is preferable that the inclination angle θ2 of the inclined surface from the bus bar main body portion and the inclination angle θ1 of the claw portion from the bus bar main body portion have a relationship of θ1 ≦ θ2. According to such a configuration, the nail portion is appropriately used as the electrode terminal by utilizing the angle difference θ2-θ1 between the inclination angle θ2 from the bus bar body portion of the inclined surface and the inclination angle θ1 from the bus bar body portion of the nail portion. In addition to being caulked, the claw portion can be caulked to the electrode terminal with a constant caulking amount (caulking condition) according to the level of the angle difference θ2−θ1. As a result, the bus bar can be stably fixed to the electrode terminal, and variations in the fixing strength of the bus bar between individual batteries constituting the assembled battery can be avoided.

  As described above, the assembled battery or the battery according to the present invention firmly fixes the bus bar to the electrode terminal, so that even if the bus bar is used in a state where vibration is generated, inconvenience occurs in the connection between the bus bar and the electrode terminal. There is nothing. Therefore, the assembled battery or battery according to the present invention is a vehicle (typically, an automobile equipped with an electric motor such as an automobile, particularly a hybrid automobile, an electric automobile, or a fuel cell automobile) on the premise of use in a state where vibration is generated. Can be preferably mounted.

It is an appearance perspective view showing typically the composition of the battery pack concerning one embodiment of the present invention. It is an appearance perspective view showing typically the composition of the bus bar concerning one embodiment of the present invention. It is sectional drawing which shows typically the structure of the bus-bar which concerns on one Embodiment of this invention. It is principal part sectional drawing which shows typically the structure of the part which fixes the bus-bar which concerns on one Embodiment of this invention to an electrode terminal. It is principal part sectional drawing which shows typically the presser ring which concerns on one Embodiment of this invention. It is principal part sectional drawing which shows the bus bar which concerns on one Embodiment of this invention typically. It is principal part sectional drawing which shows the bus bar which concerns on one Embodiment of this invention typically. It is principal part sectional drawing which shows typically the state before fixing the bus-bar which concerns on one Embodiment of this invention to an electrode terminal. It is principal part sectional drawing which shows typically the state after fixing the bus-bar which concerns on one Embodiment of this invention to an electrode terminal. It is a side view which shows typically the electrode body which concerns on one Embodiment of this invention. It is a side view which shows typically the vehicle provided with the assembled battery which concerns on one Embodiment of this invention. It is an appearance perspective view showing typically the composition of the bus bar concerning one embodiment of the present invention. It is principal part sectional drawing which shows typically the state after fixing the bus-bar which concerns on one Embodiment of this invention to an electrode terminal.

  Embodiments according to the present invention will be described below with reference to the drawings. In the following drawings, members / parts having the same action are described with the same reference numerals. Hereinafter, the structure of the assembled battery 100 including a plurality of prismatic lithium ion secondary batteries as the single battery 10 will be described in detail. However, the present invention is not intended to be limited to that described in the embodiment. Absent. In addition, the dimensional relationships (length, width, thickness, etc.) in each drawing do not reflect actual dimensional relationships.

  The configuration of the assembled battery 100 of the present embodiment will be described with reference to FIG. FIG. 1 is a perspective view schematically showing the configuration of the assembled battery 100 of the present embodiment. The assembled battery 100 is configured by connecting a plurality of chargeable / dischargeable cells 10 in series. In the illustrated example, four unit cells 10 having the same shape are arranged in series at regular intervals.

  The unit cell 10 includes an electrode body 80 (FIG. 6) that includes a positive electrode and a negative electrode, and a battery case 50 that houses the electrode body 80 and an electrolyte. The electrode body 80 of this embodiment is composed of predetermined battery constituent materials (active materials for positive and negative electrodes, current collectors for positive and negative electrodes, separators, etc.) in the same manner as a single battery equipped in a typical assembled battery. ing. In addition, a flat wound electrode body 80 described later is used as the electrode body 80 here.

  The battery case 50 of the present embodiment has a shape (box shape in the illustrated example) that can accommodate the flat wound electrode body 80. The material of the battery case 50 is not particularly limited as long as it is the same as that used for a typical unit cell. However, from the viewpoint of reducing the weight of the assembled battery itself, for example, a thin metal or synthetic resin container is used. Can be used. On the outer surface (upper surface) of the battery case 50, a positive electrode terminal 62 that is electrically connected to the positive electrode of the wound electrode body 80 and a negative electrode terminal 72 that is electrically connected to the negative electrode are provided. Then, between the adjacent unit cells 10, one positive terminal 62 and the other negative terminal 72 are connected to each other via the bus bar 20. In this way, by connecting the electrode terminals 62 and 72 of each unit cell 10 in series via the bus bar 20, the assembled battery 100 having a desired voltage is constructed.

  Next, the structure of the portion where the bus bar 20 is fixed to the electrode terminal (positive electrode terminal 62) will be described with reference to FIGS. 2A is an external perspective view of the bus bar 20, and FIG. 2B is a cross-sectional view of the bus bar 20. FIG. 3 is a cross-sectional view showing a structure of a portion where the bus bar 20 is fixed to the electrode terminal (positive electrode terminal 62). In the following, the case where the bus bar 20 is attached to the positive terminal 62 will be mainly described. However, the bus bar 20 can be attached to the negative terminal 72 in the same manner on the negative terminal 72 side.

  As shown in FIGS. 2A and 2B, the bus bar 20 is a flat main body (metal connecting member) that serves as a bus bar (metal coupling member) that electrically connects one positive terminal 62 and the other negative terminal 72 between cells. A flat plate portion) 24, a terminal insertion hole 22, and a claw portion 26 formed at a part of the periphery of the terminal insertion hole 22. The flat main body 24 is a plate-shaped metal member that connects one positive electrode terminal 62 and the other negative electrode terminal 72 between cells, and the terminal insertion hole 22 is used for inserting and attaching the positive electrode terminal 62. It is a mounting hole.

  As shown in FIG. 3, the claw portion 26 formed at a part of the peripheral edge of the terminal insertion hole 22 has a direction in which the claw portion 26 extends from the flat main body portion 24 to the tip end of the positive electrode terminal 62 (that is, a direction away from the battery case). It is bent and formed so as to rise from the main body 24 so as to be inclined. The claw portion 26 is caulked against the positive terminal 62 inserted into the terminal insertion hole 22, whereby the bus bar 20 is fixed to the positive terminal 62. That is, by using the bus bar 20 having such a configuration, the claw portion 26 which is an area portion formed to rise from the main body portion 24 as the bent portion can be effectively used for caulking and fixing.

  Therefore, in the battery pack 100 according to the present embodiment, the bus bar claw portion 26 is caulked against the positive electrode terminal 62 (that is, at least a part of the claw portion 26 and / or the positive electrode terminal 62 is deformed (collapsed) by a mechanical external force. Then, the bus bar 20 and the positive electrode terminal 62 can be securely fixed by a simple method of fixing the claw portion 26 and the positive electrode terminal 62 to each other. In addition, since the connection interface between the bus bar 20 and the positive electrode terminal 62 is stable as compared with the conventional structure in which the bus bar is screwed (because the screw is not loosened due to vibration or the like), the energization between the bus bar 20 and the positive electrode terminal 62 is performed. Therefore, it is possible to provide the assembled battery 100 with low external connection resistance.

  Hereinafter, the assembled battery 100 according to the present embodiment will be described in detail. In this embodiment, as shown in FIG. 3, the presser ring member 30 is fitted to the positive terminal 62 inserted into the terminal insertion hole 22 of the bus bar 20 closer to the tip of the positive terminal 62 than the terminal insertion hole 22. Has been. When the holding ring member 30 is pushed in the direction of the battery case, the claw portion 26 interposed between the holding ring member 30 and the battery case is caulked against the positive terminal 62.

  4A to 4C show a state of the portion where the bus bar 20 is fixed to the positive electrode terminal 62 before the assembly including the presser ring member 30, the bus bar 20, and the positive electrode terminal 62 is assembled. As shown in FIG. 4A, the positive electrode terminal 62 is a rod-shaped member having a circular cross section. The positive electrode terminal 62 has a protruding portion 66 protruding outward from the outer surface of the battery case, and the bus bar 20 is fixed to the protruding portion 66 of the positive electrode terminal 62. The material constituting the positive electrode terminal 62 is not particularly limited as long as it is used in a typical lithium secondary battery. In this embodiment, it is made of aluminum.

  As shown in FIG. 4B, the bus bar 20 includes a flat main body portion 24, a terminal insertion hole 22, and a claw portion 26 formed at a part of the peripheral edge of the terminal insertion hole 22. The terminal insertion hole 22 is an attachment hole for inserting and attaching the positive electrode terminal 62, and has a hole diameter enough to mount the protruding portion 66 of the positive electrode terminal 62 (here, the diameter is approximately 6 mm). The protruding portion 66 can be attached to the terminal insertion hole 22 without play.

The bus bar claw portion 26 is formed to be bent so as to rise from the main body portion 24 so as to be inclined from the main body portion 24 of the bus bar 20 toward the tip end direction of the positive electrode terminal 62 (that is, the direction away from the battery case).
In this embodiment, as shown in FIG. 2A, the claw portion 26 is an annular claw portion, and the annular claw portion 26 extends from the main body portion 24 to the positive terminal 62 so as to constitute the entire periphery of the terminal insertion hole 22. It is bent and formed so as to incline in the direction of the tip. By using the bus bar 20 having such a structure having the annular claw portion 26, the annular claw portion 26 can be caulked over the entire circumference of the positive electrode terminal 62, and the connection strength (caulking strength) between the bus bar 20 and the positive electrode terminal 62. In addition, the claw portion 26, which is an area portion formed so as to rise from the main body portion 24 as the bent portion, can be more effectively used for caulking and fixing.
The annular claw portion 26 is formed with a slit 28 extending outward from the terminal insertion hole 22. By forming the slit 28 in a part of the annular claw portion 26 in this way, the rigidity of the annular claw portion 26 is lowered and is easily deformed. Therefore, it becomes easy to crimp the annular claw portion 26 to the positive terminal 62. The number and shape of the slits 28 may be appropriately changed according to the specific configuration of the battery (for example, rigidity or material required for the claw portion).

  The material constituting the bus bar 20 is not particularly limited as long as it is a conductive material, but a metal material having a desired strength is preferable. As an example, a copper or aluminum bus bar can be preferably used. In this embodiment, it is made of copper. The thickness of the bus bar 20 is not particularly limited, but may be about 1.4 mm, for example.

  As shown in FIG. 4A, the presser ring member 30 is a cylindrical member that is fitted into the positive electrode terminal 62 inserted into the terminal insertion hole 22 of the bus bar 20. A through hole 32 is formed in the center portion of the presser ring member 30, and the positive terminal 62 is inserted into the through hole 32. Further, an inclined surface 36 corresponding to the inclination of the bus bar claw 26 from the bus bar main body 24 toward the tip of the positive electrode terminal is formed on the surface (lower surface in the figure) 34 of the presser ring member 30 facing the bus bar 20. .

  As shown in FIG. 5A, the inclined surface 36 of the pressing ring member 30 comes into contact with the distal end portion 26 a of the claw portion 26 when the pressing ring member 30 is put on the bus bar claw portion 26. It is formed as follows. Specifically, the inclination angle θ2 of the inclined surface 36 from the bus bar main body 24 (particularly the main body surface 24a) and the inclination angle θ1 of the claw part 26 from the bus bar main body 24 (particularly the main body surface 24a) are θ1. It may be formed in advance so as to satisfy the relationship of <θ2. According to such a configuration, when the presser ring member 30 is put on the bus bar claw portion 26, the inclined surface 36 of the press ring member reliably comes into contact with the tip end portion 26 a of the bus bar claw portion 26.

  In this embodiment, the inclination angle θ2 of the inclined surface 36 from the main body surface 24a is set to 150 °, the inclination angle θ1 of the claw portion 26 from the main body surface 24a is set to 135 °, and two inclination angles θ1 and θ2 are set. Due to the difference of 15 °, the inclined surface 36 reliably contacts the bus bar claw portion 26. Further, in this embodiment, the inclined surface 36 is provided continuously in the circumferential direction at the opening peripheral edge of the through hole 32 provided in the central portion of the presser ring member 30 and is applied over the entire periphery of the claw tip end portion 26a. It comes to touch.

  The material constituting the presser ring member 30 is not particularly limited as long as the material has a required strength. For example, the presser ring member 30 may be made of the same metal material as that of the bus bar 20 or may be made of a metal material different from that of the bus bar 20. In this embodiment, it is made of aluminum. Further, the presser ring member 30 may be made of a material having higher strength than the bus bar 20. Thereby, when the bus-bar claw part 26 is pushed in by the presser ring member 30, the presser ring member 30 can be prevented from being deformed. Moreover, you may comprise the presser ring member 30 with the material which has insulation. Thereby, insulation can be provided around the connection portion between the bus bar and the electrode terminal. The thickness of the presser ring member 30 is not particularly limited, but may be, for example, about 3 mm.

  When fixing the bus bar 20 to the positive electrode terminal 62, first, as shown in FIG. 5A, the holding ring member 30, the bus bar 20, and the positive electrode terminal 62 are assembled. Specifically, after the positive terminal 62 is inserted into the terminal insertion hole 22 of the bus bar 20, the press ring member 30 is fitted to the positive terminal 62 inserted into the terminal insertion hole 22, and the press ring member 30 is connected to the bus bar claw portion. 26. At that time, the inclined surface 36 of the presser ring member 30 is in contact with the upper end side of the tip portion 26 a of the claw portion 26, and the lower end side of the tip portion 26 a of the claw portion 26 is in contact with the outer peripheral surface 64 of the positive electrode terminal 62. To place. Each component (the press ring member 30, the bus bar 20, and the positive terminal 62) assembled in this way is set on a caulking tool (not shown).

  Then, the presser ring member 30 is pushed in the battery case direction (downward in FIG. 5A) 90 using a caulking tool (not shown). When the presser ring member 30 is pushed in the downward direction 90 in the state of FIG. 5A, the tip end portion 26a of the claw portion 26 contacting the outer peripheral surface 64 of the positive electrode terminal 62 is pressed against the outer peripheral surface 64 of the positive electrode terminal 62, While the outer peripheral surface 64 of the positive electrode terminal 62 is being shaved, it moves downward (in the direction in which the inclination angle θ1 of the claw portion 26 increases). Then, as shown in FIG. 5B, the presser ring member 30 is pushed further downward 90 until the inclination angle θ <b> 1 of the claw part 26 is substantially the same as the inclination angle θ <b> 2 of the inclined surface 36, thereby At least a part of the outer peripheral surface 64 of the portion 26a and the positive electrode terminal 62 is deformed (collapsed), and the claw portion 26 and the positive electrode terminal 62 are fixed to each other. Thus, the bus bar 20 can be fixed to the positive electrode terminal 62 by caulking the claw portion 26 against the positive electrode terminal 62 inserted into the terminal insertion hole 22.

  After the pressing ring member 30 is pushed in the downward direction 90 and the bus bar 20 is fixed to the positive electrode terminal 62 in this manner, the pressing of the pressing ring member 30 is stopped and the caulking tool (not shown) is removed from the pressing ring member 30. At this time, the presser ring member 30 receives pressure from the inside due to the springback from the deformed (crushed) busbar claw portion 26, and is integrated in a state of being covered on the busbar claw portion 26.

  As described above, in the assembled battery 100 according to the present embodiment, the flat main body 24 is used as a bus bar (metal connecting member) that electrically connects one electrode terminal and the other electrode terminal between the single cells. The terminal insertion hole 22 and a claw portion 26 formed at a part of the periphery of the terminal insertion hole 22, and the claw portion 26 extends from the body portion 24 toward the tip end of the electrode terminal 62 (that is, the battery case). The bus bar 20 is used which is bent and formed so as to stand up from the main body 24 so as to be inclined in a direction away from the main body 24. That is, by using the bus bar 20 having such a configuration, the claw portion 26 which is an area portion formed to rise from the main body portion 24 as the bent portion can be effectively used for caulking and fixing.

  Therefore, in the assembled battery 100 according to the present embodiment, the bus bar claw portion 26 is caulked with respect to the electrode terminal 62 (that is, as described above, at least a part of the claw portion 26 and / or the electrode terminal 62 is deformed by a mechanical external force. The bus bar 20 and the electrode terminal 62 can be securely fixed by a simple method of (crushing and fixing the claw portion 26 and the electrode terminal 62 to each other). In addition, since the connection interface between the bus bar 20 and the electrode terminal 62 is stable as compared with the conventional structure in which the bus bar is screwed (because the screw is not loosened due to vibration or the like), the current between the bus bar 20 and the electrode terminal 62 is energized. The property can be kept good. Furthermore, nutlessness is possible, and the number of parts and cost can be reduced.

  In addition, as shown in FIGS. 5A and 5B, when the presser ring member 30 is pushed in the downward direction 90, the tip portion 26 a of the claw portion 26 is pressed against the outer peripheral surface 64 of the electrode terminal 62, and the electrode terminal 62 It moves downward (in the direction in which the inclination angle θ1 of the claw portion 26 shown in the figure increases) while cutting the outer peripheral surface 64. At that time, the oxide film formed on the surface of the electrode terminal 62 (typically, an oxide film formed by natural oxidation of the electrode terminal) is scraped off, so that the bus bar 20 and the electrode terminal 62 are in contact with each other. Become. Therefore, the energization resistance between the bus bar 20 and the electrode terminal 62 is lowered, and the energization property between the bus bar 20 and the electrode terminal 62 is improved. Therefore, according to the present embodiment, it is possible to provide the assembled battery 100 with a low external connection resistance.

  The present inventor constructed an assembled battery in which the bus bar is caulked and fixed to the electrode terminal, and a conventional assembled battery in which the bus bar is fixed to the electrode terminal with screws (bolts and nuts), and energized between the bus bar and the electrode terminal. The resistance was compared. As a result, in the conventional battery pack in which the bus bar is screwed to the electrode terminal, the energization resistance between the bus bar and the electrode terminal is approximately 0.05 mΩ. On the other hand, in the battery pack in which the bus bar is caulked and fixed to the electrode terminal, the energization resistance between the bus bar 20 and the electrode terminal 62 is approximately 0.01 mΩ to 0.02 mΩ, and the conventional bus bar is screwed. In comparison, it was confirmed that the conductivity between the bus bar and the electrode terminal was improved. This is considered because the oxide film formed on the surface 64 of the electrode terminal 62 was scraped off when the claw portion 26 was caulked to the electrode terminal 62, and the bus bar 20 and the electrode terminal 62 were in contact with each other. It is done.

  Furthermore, in the configuration according to the present embodiment, the bus bar claw portion 26 is an annular claw portion 26 that rises in the distal direction and is formed so as to constitute the entire periphery of the terminal insertion hole 22. The annular claw portion 26 is caulked over the entire circumference of the electrode terminal 62. By using the bus bar 20 having such a structure, the annular claw portion 26 can be caulked over the entire circumference of the electrode terminal 62, and the connection strength (caulking strength) between the bus bar 20 and the electrode terminal 62 is further increased. The claw portion 26 which is an area portion formed so as to rise from the main body portion 24 as the bent portion can be more effectively used for caulking and fixing. In the bus bar 20 having such a structure, since the annular claw portion 26 is caulked over the entire circumference in the circumferential direction of the electrode terminal 62, the force is exerted in the pulling direction (the axial direction of the electrode terminal, the vertical direction in FIG. 3). Even if acts, it can exert a great resistance.

  Furthermore, in the configuration according to the present embodiment, the press ring member 30 is fitted to the electrode terminal 62 inserted into the terminal insertion hole 22 of the bus bar 20 closer to the tip of the electrode terminal 62 than the terminal insertion hole 22. Yes. Then, when the press ring member 30 is pushed in the battery case direction 90, the claw portion 26 interposed between the press ring member 30 and the battery case is caulked to the electrode terminal 62. According to such a configuration, the bus bar 20 can be fixed simply by pushing in the presser ring member 30, and the assembly workability is good. Therefore, construction of an assembled battery or the like can be performed quickly. Further, the bus bar 20 can be fixed simply by pushing the presser ring member 30, and a wide tooling space (a gap for inserting a tool such as a wrench) is not required around the electrode terminal 62. Therefore, even if it is a compact assembled battery with a short distance between terminals, the bus bar 20 can be fixed easily.

  The presser ring member 30 may be removed from the bus bar 20 after the bus bar 20 is fixed, but it is preferable that the presser ring member 30 be integrated with the bus bar 20. In this embodiment, the presser ring member 30 receives pressure from the inside by the spring back from the deformed (crushed) bus bar claw portion 26 and is integrated in a state of being covered on the bus bar claw portion 26. According to such a configuration, the reaction force generated in the deformed (crushed) claw portion 26 can be pressed by the press ring member 30, and the bus bar 20 can be firmly and stably fixed.

  Further, in the configuration according to the present embodiment, the inclined surface 36 corresponding to the inclination of the claw portion 26 from the bus bar main body portion 24 to the distal end of the electrode terminal 62 is formed on the surface 34 of the holding ring member 30 facing the bus bar 20. Has been. In the state before the bus bar 20 is fixed, the inclination angle θ2 of the inclined surface 36 from the bus bar main body 24 and the inclination angle θ1 of the claw 26 from the bus bar main body 24 satisfy θ1 <θ2 (FIG. 5A). When the bus bar 20 is fixed, the inclination angle θ1 of the claw portion 26 from the bus bar main body portion 24 is substantially the same as the inclination angle θ2 of the inclined surface 36 from the bus bar main body portion 24 ( The pressing ring member 30 is pushed in the downward direction 90 until θ1 = θ2 and FIG. 5B).

  According to such a configuration, the angle difference θ2−θ1 (FIG. 5A) between the inclination angle θ2 of the inclined surface 36 from the bus bar main body portion 24 and the inclination angle θ1 of the claw portion 26 from the bus bar main body portion 24 is obtained. Since the claw part 26 is appropriately caulked to the electrode terminal 62, the claw part 26 is caulked to the electrode terminal 62 at a constant caulking amount (caulking degree) according to the level of the angle difference θ2-θ1 (FIG. 5A). It can be tightened. As a result, the bus bar 20 can be stably fixed to the electrode terminal 62, and variations in the fixing strength of the bus bar 20 between individual batteries constituting the assembled battery 100 and the like can be avoided.

  According to such a configuration, the claw portion 26 is crimped to the electrode terminal 62 by utilizing the angle difference θ2-θ1 between the inclination angle θ2 of the inclined surface 36 and the inclination angle θ1 of the claw portion 26 shown in FIG. 5A. A constant caulking amount (caulking condition) can be obtained at a level corresponding to the angle difference θ2−θ1 minutes. Thereby, the nail | claw part 26 can be crimped to the electrode terminal 62 appropriately and stably. Moreover, it can avoid that the connection intensity | strength of a bus-bar and an electrode terminal arises between each single battery which comprises an assembled battery. In addition, this invention is not limited to the said structure. For example, even in this case, the claw portion 26 can be caulked to the electrode terminal 62 at a level corresponding to the change in the inclination angle θ1 of the claw portion 26 before and after caulking.

  Next, the configuration of the cell 10 that can be used in the present embodiment, each material that forms the cell 10, and the like will be described in detail with reference to FIG. 6. The assembled battery 100 according to the present embodiment may be an assembled battery 100 in which a rechargeable secondary battery is a single battery 10 and a plurality of such single batteries 10 are connected in series. The configuration is not particularly limited. The type of the unit cell is not limited to the above-described lithium ion battery, and a nickel metal hydride battery, an electric double layer capacitor, and the like can be cited as a unit cell configuration suitable for implementing the present invention.

  As described above, the unit cell 10 includes an electrode body including a positive electrode and a negative electrode, and a battery case 50 that accommodates the electrode body and an electrolyte. The configuration of the wound electrode body housed in the battery case 50 will be described in detail. The wound electrode body according to the present embodiment includes a sheet-like positive electrode (hereinafter referred to as “positive electrode sheet”) and a sheet-like negative electrode (hereinafter referred to as “negative electrode sheet”), similarly to the wound electrode body of a normal lithium ion battery. Laminated together with a total of two sheet-like separators (hereinafter referred to as “separator sheets”), and the positive electrode sheet and the negative electrode sheet are wound with a slight shift, and then the obtained wound body is crushed from the side surface direction. It is a flat wound electrode body 80 produced by making it.

  As shown in FIG. 6, in the lateral direction with respect to the winding direction of the wound electrode body 80, as a result of being wound slightly shifted as described above, a part of the ends of the positive electrode sheet 82 and the negative electrode sheet 84 are respectively It protrudes outward from the wound core portion 81 (that is, the portion where the positive electrode active material layer forming portion of the positive electrode sheet 82, the negative electrode active material layer forming portion of the negative electrode sheet 84, and the separator sheet 86 are closely wound). A positive electrode lead terminal 82B and a negative electrode lead terminal 84B are attached to the protruding portion 82A (that is, the non-forming portion of the positive electrode active material layer) 82A and the protruding portion 84A (that is, the non-forming portion of the negative electrode active material layer) 84A, respectively. Are electrically connected to the positive terminal 62 and the negative terminal 72, respectively.

In addition, the material and member itself which comprise this winding electrode body may be the same as that of the electrode body of the conventional lithium ion battery, and there is no restriction | limiting in particular. For example, the positive electrode sheet can be formed by applying a positive electrode active material layer for a lithium ion battery on a long positive electrode current collector. For the positive electrode current collector, an aluminum foil (this embodiment) or other metal foil suitable for the positive electrode is preferably used. As the positive electrode active material, one or more of materials conventionally used in lithium ion batteries can be used without any particular limitation. Preferable examples include LiMn ₂ O ₄ , LiCoO ₂ , LiNiO _{2 and the} like.

  On the other hand, the negative electrode sheet can be formed by applying a negative electrode active material layer for a lithium ion battery on a long negative electrode current collector. For the negative electrode current collector, a copper foil (this embodiment) or other metal foil suitable for the negative electrode is preferably used. As the negative electrode active material, one or more of materials conventionally used in lithium ion batteries can be used without any particular limitation. Preferable examples include carbon-based materials such as graphite carbon and amorphous carbon, lithium-containing transition metal oxides and transition metal nitrides.

  Moreover, what was comprised with porous polyolefin resin as a suitable separator sheet used between positive and negative electrode sheets is mentioned. When a solid electrolyte or a gel electrolyte is used as the electrolyte, there may be a case where a separator is unnecessary (that is, in this case, the electrolyte itself can function as a separator).

Next, the configuration of the electrolyte housed in the battery case 50 together with the wound electrode body will be described. The electrolyte of this embodiment is a lithium salt such as LiPF ₆ . In the present embodiment, an appropriate amount (for example, concentration 1M) of a lithium salt such as LiPF ₆ is dissolved in a nonaqueous electrolytic solution such as a mixed solvent of diethyl carbonate and ethylene carbonate (for example, a mass ratio of 1: 1) to prepare an electrolytic solution. It is used as

  The unit cell 10 of the present embodiment is constructed by housing the wound electrode body in the battery case 50 and injecting and sealing the electrolytic solution. Then, by arranging the cells 10 in a predetermined direction (parallel in this embodiment) and connecting one positive terminal 62 and the other negative terminal 72 in series by the bus bar 20 between the adjacent single cells 10, The assembled battery 100 having a desired voltage is constructed.

  As described above, in the battery pack 100 according to the present embodiment, the bus bar 20 is firmly fixed to the electrode terminal 62. Therefore, even if the bus bar 20 is used in a state where vibration is generated, the bus bar 20 and the electrode terminal 62 are connected. There will be no inconvenience. Therefore, the assembled battery 100 according to the present embodiment can be preferably mounted on a vehicle that is assumed to be used in a state where vibration is generated. Therefore, in the present invention, as schematically shown in FIG. 7, a vehicle (typically, an automobile equipped with an electric motor such as an automobile, particularly a hybrid automobile, an electric automobile, or a fuel cell automobile) provided with such an assembled battery 100 as a power source. 1 can be provided. When mounted on a vehicle such as an automobile, a larger number of cells can be connected in series, and an exterior cover for protecting the main part (unit cell group, etc.) of the assembled battery is applied to a predetermined part of the vehicle. Parts for fixing the assembled battery can be equipped, but the presence or absence of such equipment does not affect the technical scope of the present invention.

  As mentioned above, although this invention was demonstrated by suitable embodiment, such description is not a limitation matter and of course various modifications are possible.

  For example, in the present embodiment, as shown in FIG. 5B, the inclination angle θ1 of the claw portion 26 from the bus bar main body 24 is substantially the same as the inclination angle θ2 of the inclined surface 36 from the bus bar main body 24 (θ1 = θ2). 5B), the presser ring member 30 is pushed in the downward direction 90. However, the present invention is not limited to this. For example, if a sufficient caulking amount (caulking condition) is obtained, the inclination angle θ1 of the claw portion 26 from the bus bar main body portion 24 is smaller than the inclination angle θ2 of the inclined surface 36 from the bus bar main body portion 24. In some cases, the pressing of the presser ring member 30 may be stopped (θ1 ≦ θ2).

  Further, in the present embodiment, as shown in FIG. 2A, an example in which two slits 28 are formed in a part of the annular claw portion 26 is shown in order to facilitate the caulking of the annular claw portion 26. It is not limited to. For example, two or more slits having a shape different from the slit shape of FIG. 2A may be formed. In the example of FIG. 8, four slits 28 wider than the slits of FIG. 2A are formed. Thus, by appropriately changing the number and shape of the slits formed in the annular claw portion 26, the rigidity of the annular claw portion 26 can be appropriately adjusted, and the electrode terminal can be caulked with a desired caulking strength.

  Further, in the present embodiment, the presser ring member 30 is integrated in a state where it is covered with the bus bar 20 without being removed from the bus bar 20 after the bus bar 20 is fixed, but is not limited thereto. For example, as shown in FIG. 9, the pressing ring member 30 may be removed from the bus bar 20 after the bus bar 20 is fixed. Thereby, the structure around the fixed part of the bus bar 20 and the electrode terminal 62 can be simplified.

  Furthermore, in this embodiment, the claw part 26 which comprises the periphery of the terminal insertion hole 22 inclines toward the front-end | tip direction of the electrode terminal 62 from the bus-bar main-body part 24 (it protrudes upwards in FIG. 2A and FIG. 2B). An example of being formed is shown, but the present invention is not limited to this. For example, the front and back surfaces of the bus bar 20 shown in FIGS. 2A and 2B may be turned over (that is, inverted so that the claw portion 26 protrudes downward). In this case, the claw portion 26 constituting the periphery of the terminal insertion hole 22 is formed so as to be inclined from the bus bar main body portion 24 toward the battery case. Even in the bus bar having such a structure, by crimping the claw portion 26 formed so as to be inclined from the bus bar main body portion 24 toward the battery case with respect to the electrode terminal 62 inserted into the terminal insertion hole 22, The bus bar 20 can be appropriately fixed to the electrode terminal 62.

  Furthermore, the terminal fixing structure of the bus bar according to the present invention can be widely applied to applications for connecting electrode terminals in individual cells constituting the assembled battery. For example, as shown in FIG. 1, the present invention provides a battery 10 that includes a battery case 50 that houses an electrode body and an electrode terminal 62 that protrudes from the outer surface of the battery case 50.

  The battery 10 is connected to the electrode terminal 62, and the electrode terminal 62 and a terminal outside the battery (in the example of FIG. 1, when the assembled battery 100 including a plurality of the batteries 10 according to the present invention as unit cells is constructed, A bus bar 20 for connecting the battery 10 and the electrode terminal 72 provided in the adjacent unit cell). The battery external terminal 72 is not limited to the electrode terminal 72 included in the adjacent unit cell when the battery is assembled, but may be another battery external terminal (for example, a terminal included in a battery external device such as an inverter). As shown in FIG. 3, the bus bar 20 is a metal member having a plate-like main body portion 24, and includes a terminal insertion hole 22 into which the electrode terminal 62 is inserted and at least a part of the periphery of the terminal insertion hole 22. The claw portion 26 is configured to have a claw portion 26 formed so as to be inclined from the main body portion 24 of the bus bar toward the tip end of the electrode terminal 62 or the battery case. Then, the bus bar 20 may be fixed to the electrode terminal 62 by caulking the claw portion 26 against the electrode terminal 62 inserted into the terminal insertion hole 22.

  In such a configuration, as a bus bar (metal connecting member) that electrically connects the electrode terminal 62 and a terminal outside the battery, the flat main body 24, the terminal insertion hole 22, and a peripheral edge of the terminal insertion hole 22 are provided. And the claw 26 is in the direction of the tip of the electrode terminal 62 (ie, the direction away from the battery case) or the direction of the battery case (ie, the direction of approaching the battery case). The bus bar 20 is used which is bent so as to stand up from the main body 24 so as to be inclined. That is, by using the bus bar 20 having such a configuration, the claw portion 26 which is an area portion formed to rise from the main body portion 24 as the bent portion can be effectively used for caulking and fixing.

DESCRIPTION OF SYMBOLS 10 Cell 20 Bus bar 22 Terminal insertion hole 24 Main body part 26 Claw part 26a Tip part 28 of claw part Slit 30 Press ring member 32 Through hole 34 Surface 36 opposite to the bus bar of the press ring member Slope 50 Battery case 62 Positive electrode terminal 64 Outer peripheral surface 72 Negative electrode terminal 80 Winding electrode body 81 Winding core portion 82 Positive electrode sheet 82B Positive electrode lead terminal 84 Negative electrode sheet 84B Negative electrode lead terminal 86 Separator sheet 100 Battery assembly

Claims (11)

An assembled battery in which a plurality of cells are electrically connected,
A plurality of unit cells each including a battery case that houses an electrode body, and electrode terminals that protrude from the outer surface of the battery case;
In the plurality of unit cells, between the adjacent unit cells, one electrode terminal and the other electrode terminal are connected to each other via a bus bar,
The bus bar is a metal member having a plate-like main body portion for connecting the electrode terminals, and a terminal insertion hole for inserting the electrode terminal, and a claw portion constituting at least a part of a peripheral edge of the terminal insertion hole And having a claw portion formed so as to be inclined from the main body portion of the bus bar toward the tip end direction of the electrode terminal or the battery case,
The assembled battery, wherein the bus bar is fixed to the electrode terminal by caulking the claw portion with respect to the electrode terminal inserted into the terminal insertion hole. The claw portion is an annular claw portion that rises from the bus bar main body portion formed in the peripheral direction of the terminal insertion hole in the tip direction or the battery case direction,
The assembled battery according to claim 1, wherein the annular claw portion is caulked over the entire circumference of the electrode terminal.   The assembled battery according to claim 2, wherein a slit extending outward from the terminal insertion hole is formed in the annular claw portion. The electrode terminal inserted into the terminal insertion hole of the bus bar is fitted with a press ring member closer to the tip of the electrode terminal than the terminal insertion hole,
2. The claw portion interposed between the presser ring member and the battery case is caulked against the electrode terminal by the presser ring member being pushed in the battery case direction. The assembled battery according to any one of 3 to 3. On the surface of the pressing ring member facing the bus bar, an inclined surface corresponding to the inclination of the claw portion from the bus bar main body portion toward the tip end of the electrode terminal is formed,
The inclination angle θ2 of the inclined surface from the bus bar main body portion and the inclination angle θ1 of the claw portion from the bus bar main body portion are in a relationship of θ1 ≦ θ2. Battery pack. A battery case that houses the electrode body;
A battery comprising an electrode terminal protruding on an outer surface of the battery case,
A bus bar connected to the electrode terminal and connecting the electrode terminal and a terminal outside the battery;
The bus bar is a metal member having a plate-shaped main body, and includes a terminal insertion hole into which the electrode terminal is inserted, and a claw that forms at least a part of a peripheral edge of the terminal insertion hole. A claw portion formed so as to be inclined from the portion toward the tip of the electrode terminal or toward the battery case,
The battery, wherein the bus bar is fixed to the electrode terminal by caulking the claw portion with respect to the electrode terminal inserted into the terminal insertion hole. The claw portion is an annular claw portion that rises from the bus bar main body portion formed so as to constitute the entire circumference of the terminal insertion hole in the electrode terminal tip direction or the battery case direction,
The battery according to claim 6, wherein the annular claw portion is caulked over the entire circumference of the electrode terminal.   The battery according to claim 7, wherein the annular claw portion is formed with a slit extending outward from the terminal insertion hole. The electrode terminal inserted into the terminal insertion hole of the bus bar is fitted with a press ring member closer to the tip of the electrode terminal than the terminal insertion hole,
7. The claw portion interposed between the press ring member and the battery case is caulked with respect to the electrode terminal when the press ring member is pushed in the battery case direction. The battery according to any one of 8 to 8. On the surface of the pressing ring member facing the bus bar, an inclined surface corresponding to the inclination of the claw portion from the bus bar main body portion toward the tip end of the electrode terminal is formed,
The inclination angle θ2 of the inclined surface from the bus bar main body portion and the inclination angle θ1 of the claw portion from the bus bar main body portion are in a relationship of θ1 ≦ θ2. Battery.   A vehicle comprising the assembled battery according to any one of claims 1 to 5 or the battery according to any one of claims 6 to 10.

Images