JP2009252373A - Battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the number of components and man-hours in production by simplifying the structure of a battery pack, facilitate miniaturization, thinning, and lighting in weight, and enhance stiffness as the whole battery pack and reliability of connection with an outside terminal. <P>SOLUTION: A battery pack 1 is composed of a battery 10 and an end case 11 including an outside connection terminal keeping conductivity with the a terminal of an outside apparatus by surface contact, and the battery 10 and the end case 11 are joined with a joining pin 12. In addition, the joining pin 12 functions as a lead member for making conductive a second electrode terminal having a polarity different from that of an electrode terminal 19 which is a first electrode terminal of the battery 10 and an outside connection terminal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a battery pack. More specifically, the present invention mainly relates to an improvement in the structure of a battery pack.

  Secondary batteries such as lithium ion secondary batteries and nickel metal hydride batteries are generally distributed in the market as battery packs integrated with a circuit board including a charge / discharge safety circuit for controlling charge / discharge of the battery. Battery packs are required to be small, thin, and lightweight, have low connection resistance with external terminals such as electronic devices, and have high connection reliability. In particular, in the present situation where demand for portable small electronic devices is increased and these further miniaturization and multi-function are progressing, it is an urgent need to miniaturize the battery pack without reducing the battery capacity. Here, examples of the portable small electronic device include a mobile phone, a personal computer, a portable information terminal, and a digital still camera.

  A battery pack is usually composed of a secondary battery and a large number of parts. The component is a small component having a dimension of about several millimeters or less. Therefore, simply reducing the size of the battery pack decreases the battery capacity and reduces the number of parts, thereby requiring high dimensional accuracy and further complicating the assembly process.

  Conventionally, as a battery pack, for example, a battery pack in which a secondary battery and a circuit board are integrated by a resin mold is known (see, for example, Patent Document 1). An example of a battery pack having the same configuration as that of Patent Document 1 and further simplified is a battery pack 50 shown in FIG. FIG. 8 is an exploded perspective view showing a simplified configuration of the battery pack 50. The battery pack 50 includes a battery 51, a negative electrode lead plate 52, a positive electrode lead plate 53, a circuit board 54, a second insulating paper 55, a resin molded body 56, an end case 57, and a label 58.

  The battery 51 includes a power generation element (not shown) and a battery can that houses the power generation element. The electrode terminal 60 is provided on one end surface 51a of the battery 51, and the Ni plate 61, the first insulating paper 62, and the rivet 63 are mounted. . The battery can functions as a positive electrode terminal. The electrode terminal 60 is connected to the negative electrode lead plate 52. The one end face 51 a and the positive electrode lead plate 53 are connected via the Ni plate 61. The first insulating paper 62 prevents conduction between the one end face 51 a and the negative electrode lead plate 52. The rivet 63 joins a sealing plate (not shown) and the opening of the battery can to seal the battery can.

  A safety protection element (not shown) is disposed between the negative electrode lead 52 and the second insulating paper 55. An electronic component (not shown) is mounted on the surface of the circuit board 54 opposite to the surface facing the negative electrode lead plate 52 and the positive electrode lead plate 53, and external connection terminals and test terminals (not shown) are arranged. The negative electrode lead plate 52, the positive electrode lead plate 53, the circuit board 54, and the second insulating paper 55 are integrated and joined to the one end surface 51a of the battery 51 by soldering or the like. Thereafter, the negative electrode lead plate 52 and the positive electrode lead plate 53 are bent so that the surface on which the electronic component of the circuit board 54 is mounted faces upward in the vertical direction. In this state, the molding using the synthetic resin is performed, and the resin mold body 56 including the parts 52 to 55 is formed. Although not shown, the external connection terminal and the test terminal are exposed on the upper surface in the vertical direction of the resin mold body 56.

  Further, an end case 57 is mounted on the upper surface in the vertical direction of the resin mold body 56. The mounting of the end case 57 is often performed by molding. A test terminal window 57a and an external connection window 57b are formed in the end case 57, and the test terminal and the external connection terminal are exposed, respectively. After confirming the operation by the test terminal, the label 58 is attached to the test terminal window 57a, and the test terminal is insulated.

  The battery pack 50 has succeeded in reducing the number of parts to the limit as a battery pack using molding. However, the electrode terminal 60 and the battery can of the battery 51 are connected via the plurality of negative electrode lead plates 52 and the positive electrode lead plate 53, the point that two moldings are required, the mechanical strength of the battery pack 50, particularly There remains room for further improvement in terms of torsional strength.

  Moreover, for example, a battery pack including a battery, a circuit board, an end case, and a screw has been proposed (see, for example, Patent Document 2). Here, the battery includes a power generation element, a battery can that accommodates the power generation element and serves as an electrode terminal of one polarity, and an electrode terminal of the other polarity provided on one end surface of the battery can. The circuit board includes a charge / discharge safety circuit that controls charge / discharge of the battery, and is disposed on one end surface of the battery. The end case includes external connection terminals and further accommodates a circuit board therein. The head of the screw engages with both ends of the end case and penetrates both ends of the end case, and the tip thereof is screwed and fixed to both ends of one end face of the battery.

According to the battery pack of Patent Literature 2, the structure is made compact by joining the battery and the end case using screws. In addition, the reliability and productivity of the battery pack are improved. However, in the battery pack of Patent Document 2, the screw is used only for joining the battery and the end case. This is apparent from the fact that a plurality of connection brackets that function as electrode lead plates are used as parts of the battery pack. That is, Patent Document 2 does not describe a configuration in which a screw is used as a lead member. Further, the battery pack of Patent Document 2 leaves room for further improvement in terms of reducing the number of parts.
JP 2003-308815 A Japanese Patent Laid-Open No. 2006-164551

  The present inventor first invented a battery pack in which a battery and an end case are joined by a joining pin in view of the problems of the prior art, and previously filed a patent application (Japanese Patent Application No. 2007-48448). However, also in this battery pack, a lead member corresponding to the positive electrode of the battery and a lead member corresponding to the negative electrode of the battery are provided separately from the joining pins. That is, it is apparent that this patent application does not disclose the technical idea of using the joining pin as a lead member for conducting the battery electrode terminal and the external connection terminal.

  An object of the present invention is to have a simple structure capable of reducing the size, size, and weight of components, having good productivity, and having low connection resistance with a terminal of an external device, and reliable connection. It is to provide a battery pack with high performance.

  As a result of intensive research in order to solve the above problems, the present inventor conducted the connection between the battery electrode terminal and the external connection terminal via the screw in the configuration in which the battery and the end case are joined by the screw. The present inventors have found that the number of parts can be reduced, and the structure can be made compact and the productivity can be improved. Furthermore, by joining the battery and the end case with screws and making the end case as an integrally molded product, the mechanical strength of the battery pack is improved, and in particular, the torsional strength of the battery pack is significantly improved. I found it. The present inventor has completed the present invention based on these findings.

That is, the present invention
A battery having an end surface in which a recess is formed and the first electrode terminal is provided, and a second electrode terminal having a polarity different from that of the first electrode terminal;
An end case including an insertion hole and an external connection terminal that makes point contact with a terminal of an external device, the insertion hole is formed to penetrate the end case in the thickness direction and communicate with the recess, and the external connection terminal An end case including a first external connection terminal electrically connected to one electrode terminal and a second external connection terminal electrically connected to the second electrode terminal;
The present invention relates to a battery pack that includes a joining pin that is mounted and fixed in an insertion hole and a recess to join the battery and the end case and to connect the second electrode terminal and the second external connection terminal.

The end case is preferably an integrally molded product made of synthetic resin.
It is preferable that the end case further includes at least one selected from the group consisting of a circuit board, a test connection terminal, and a safety protection element.
The battery is preferably a secondary battery.
More preferably, the battery is a lithium ion secondary battery.

It is preferable that the end portion on the end case side engages with the end case.
In the battery pack according to another aspect of the present invention, the first electrode terminal is electrically connected to the first external connection terminal via the joining pin.

The battery pack of the present invention preferably further includes a resin layer formed on the surface of the joined body by the joining pins of the battery and the end case, and an exterior body attached to the surface of the resin layer.
The resin layer is preferably formed by inserting a joined body of joining pins of the battery and the end case into a mold and performing insert molding.
It is preferable that an exterior body is affixed on the resin layer surface by an adhesive agent or ultrasonic welding.

The battery pack of the present invention has a very compact structure in which a battery and an end case including an external connection terminal are joined by a joining pin. In addition, the joining pin also has a function as a lead member for conducting the battery electrode terminal and the external connection terminal. Based on such a configuration, the present invention can achieve a reduction in the number of components, an improvement in battery pack rigidity, a reduction in the size, thickness and weight of the battery pack, and an improvement in productivity.
Further, in the battery pack of the present invention, the battery itself is not miniaturized, so that the battery capacity does not decrease. Depending on the end case structure, the end case can be further reduced in size and the battery can be increased in size, so that the battery capacity can be increased.

  The battery pack of the present invention is characterized in that the battery and the end case are joined using a joining pin that functions as a lead member. By adopting such a configuration, various advantages can be obtained. For example, the structure of the battery pack is simplified and becomes very compact. In addition, since a plurality of parts such as a plurality of electrode lead plates used in the conventional battery pack can be omitted, the connection distance with an external electric / electronic device can be shortened. Thereby, connection resistance with the terminal of an electrical / electronic device becomes still smaller, and the reliability of connection improves more.

  In addition to the electrode lead plate, it is possible to omit metal plates that connect the electrode lead plate and the battery can, insulating parts such as insulating paper, rivets, etc. For example, the reduction rate of parts reaches 50%. . Further, it is possible to omit a soldering process for connecting the electrode lead plates, a bending process for bending the electrode lead boards, a partial insulating process, and the like. Therefore, the production process is simplified, the defective product rate and the manufacturing cost are reduced, and the productivity is remarkably improved.

  Further, by joining the end case and the battery with a joining pin and making the end case an integrally molded product, the mechanical strength of the battery pack is improved and the durability is increased as compared with the conventional battery pack. In particular, since the torsional strength of the battery pack is remarkably improved, the battery pack of the present invention is useful as a power source for electronic devices having a risk of dropping such as portable electronic devices. Further, the configuration in which the battery and the end case are joined with the joining pin increases the degree of freedom in shape, and can relatively easily cope with changes in the specifications of the electronic and electrical equipment.

  In the present specification, the external connection terminal of the battery pack of the present invention is in point contact with the terminal of the external device. Point contact means that the tip portions of both terminals are in contact, or the surface portion of one terminal and the tip portion of one terminal are in contact. In the point contact, the contact portions of both terminals are fixed by spot welding, for example. On the other hand, the surface contact means that a part or the entire surface of the external connection terminal is in contact with a part or the entire surface of the terminal of the external device. The external device is a device that receives power supply from the battery pack of the present invention, mainly an electric device and an electronic device.

  FIG. 1 is an exploded perspective view showing a simplified configuration of a battery pack 1 that is one embodiment of the present invention. FIG. 2 is a perspective view showing an appearance of the battery pack 1 shown in FIG. FIG. 3 is a top view of the battery pack 1 shown in FIG. FIG. 4 is a side view of the battery pack 1 shown in FIG. FIG. 5 is a vertical cross-sectional view showing a simplified configuration of one end portion 10a of the battery 10 included in the battery pack 1 shown in FIG. In addition, illustration of the explosion-proof valve 30 is abbreviate | omitted in FIG. The battery pack 1 shown in FIG. 1 has a flat shape and includes a battery 10, an end case 11, a joining pin 12, and an insulating label 13.

  The battery 10 is preferably a secondary battery, and more preferably a lithium ion secondary battery. The battery 10 is a flat battery having, for example, the structure shown in FIGS. 1 and 5 and having an oval cross section. FIG. 5A is a vertical cross-sectional view showing a simplified configuration of one end 10a of the battery 10 and its vicinity. FIG. 5B is an enlarged longitudinal sectional view showing the configuration of one recess 18 and its vicinity. FIG. 5C is an enlarged longitudinal sectional view showing the configuration of the electrode terminal 19 and the vicinity thereof. The battery 10 includes a battery can 15, a sealing plate 16, and an exterior body 17.

  The battery can 15 is a bottomed cylindrical container-like member having an oval cross-sectional shape, and houses a power generation element (not shown). Further, the battery can 15 has an opening for accommodating the power generation element at one end. This opening is sealed by the sealing plate 16 after the power generation element is accommodated. The battery can 15 can be made of aluminum, for example. Further, lead wires are wired inside the battery can 15 so that the battery can 15 is an electrode terminal having a polarity different from that of the electrode terminal 19 described later. That is, the battery can 15 becomes the second electrode terminal. In the present embodiment, the battery can 15 is a positive electrode terminal.

  The power generation element includes an electrode group and an electrolytic solution. The electrode group includes a positive electrode, a negative electrode, and a separator, and is produced by winding or laminating the positive electrode and the negative electrode with the separator interposed therebetween. The positive electrode includes a positive electrode active material layer and a positive electrode current collector. When the battery 10 is, for example, a lithium ion secondary battery, the positive electrode active material layer includes, for example, a positive electrode active material such as a lithium nickel composite oxide, a lithium cobalt composite oxide, and a lithium manganese composite oxide, and a conductive agent such as a carbon material. And a binder such as polyethylene, polypropylene, and fluororesin. For the positive electrode current collector, for example, an aluminum foil, an aluminum alloy foil, a stainless steel foil, or the like can be used.

  The negative electrode includes a negative electrode active material layer and a negative electrode current collector. When the battery 10 is, for example, a lithium ion secondary battery, the negative electrode active material layer includes, for example, a negative electrode active material such as graphite and carbon black, a binder such as styrene-butadiene rubber particles, a fluorine resin, and an increase in carboxymethyl cellulose. Contains a sticky agent. Alternatively, the negative electrode active material layer may be formed by evaporating a negative electrode active material such as silicon, silicon alloy, silicon oxide, tin, tin alloy, or tin oxide on the negative electrode current collector. For the negative electrode current collector, for example, copper foil, copper alloy foil, stainless steel foil or the like can be used.

For the separator, for example, a resin porous membrane can be used. Examples of the resin for the separator include polyolefins such as polyethylene and polypropylene.
Moreover, when the battery 10 is a lithium ion secondary battery, for example, a nonaqueous electrolyte containing, for example, a lithium salt and various nonaqueous solvents can be used as the electrolytic solution. After the battery can 15 is sealed with the sealing plate 16, the electrolytic solution is injected into the battery can 15 through the liquid injection hole 20 a formed in the sealing plate 16.
In addition, a positive electrode, a negative electrode, a separator, and electrolyte solution are not limited to what was mentioned above, What is normally used in the field | area of a lithium ion secondary battery can be used.

  In the present embodiment, the battery can 15 has a bottomed cylindrical shape having an oval cross-sectional shape, but is not limited thereto. For example, the battery can 15 has a bottomed cross-sectional shape of a rectangle or a rounded rectangle. You may use the battery can which is a container.

  The sealing plate 16 is a metal plate-like member for sealing the opening of the battery can 15, and is attached to the battery can 15 so as to be electrically connected to the battery can 15 at both ends in the longitudinal direction. The sealing plate 16 is attached to the battery can 15 by, for example, using aluminum made of the sealing plate 16 and the battery can 15 and laser welding them. The surface of the sealing plate 16 becomes one end face 10 a of the battery 10. Further, the sealing plate 16 is formed with a recess 18, an electrode terminal forming hole 19 a, a liquid injection hole 20 a, and an explosion-proof valve 30.

  One recess 18 is formed at each end of the sealing plate 16 in the longitudinal direction. The recess 18 preferably has a circular cross-sectional shape. The inner diameter and depth of the recess 18 are appropriately selected according to the design dimensions of the battery pack 1 and the dimensions and materials of the joining pins 12. It is preferable to appropriately select 2.7 mm and the depth from the range of 1.0 to 3.0 mm. As will be described later, the tip of the joining pin 12 is attached to the recess 18 through an insertion hole 28 formed in the end case 11 and is fixed so as to contact the inner surface of the recess 18. Thereby, the joining pin 12 and the sealing board 16 are connected so that conduction | electrical_connection is possible.

  The electrode terminal forming hole 19a is formed so as to penetrate the sealing plate 16 in the thickness direction at substantially the center in the longitudinal direction of the sealing plate 16, and has a large diameter upper hole and a small diameter communicating with the upper hole. It consists of holes. The upper hole and the lower hole are preferably formed so that their axes coincide. The electrode terminal 19 is attached to the electrode terminal forming hole 19a via a gasket 21 which is an insulating member. A part of the electrode terminal 19 protrudes outward from the surface (one end face 10 a) of the sealing plate 16. The electrode terminal 19 is connected to a terminal 22 provided around the electrode terminal forming hole 19a so as to be conductive. The electrode terminal 19 is attached to the electrode terminal forming hole 19a by, for example, laser welding. The electrode terminal 19 becomes a first electrode terminal.

  The gasket 21 is a resin member having a hollow circular shape corresponding to the internal space of the electrode terminal forming hole 19a. The terminal 22 is electrically connected to an electrode having a polarity opposite to that of the electrode connected to the battery can 15 by a lead wire (not shown). In the present embodiment, the terminal 22 is a negative electrode terminal. The insulating member 23 is provided around the electrode terminal forming hole 19a and between the sealing plate 16 and the terminal 22 to insulate them. The insulating member 23 is made of an insulating material such as synthetic resin, for example.

The liquid injection hole 20a is formed so as to penetrate the sealing plate 16 in the thickness direction between the one concave portion 18 in the longitudinal direction of the sealing plate 16 and the electrode terminal forming hole 19a. As described above, the injection hole 20a is formed for injecting the electrolyte into the battery can 15. After the electrolytic solution is injected, the injection hole 20 a is closed by the sealing plug 20. The sealing plug 20 is fixed to the sealing plate 16 by welding or the like, for example.
The explosion-proof valve 30 is provided to prevent heat from being generated inside the battery 10 due to overcharge, an internal short circuit, etc., and the internal pressure is increased to cause the battery 10 to burst. When the internal pressure of the battery 10 increases more than necessary, the explosion-proof valve 30 is opened, and the contents of the battery 10 are discharged from the opened part to the outside of the battery 10, thereby preventing the battery 10 from bursting.

For example, various synthetic resin films can be used for the outer package 17 attached around the battery can 15. For example, a polyethylene terephthalate film is preferable. Arbitrary printing, design, etc. may be given to the outer peripheral surface of the exterior body 17 when the exterior body 17 is stuck to the battery can 15. In order to attach the outer package 17 to the peripheral surface of the battery can 15, for example, a method using an adhesive or a pressure-sensitive adhesive, a method using ultrasonic welding, or the like can be employed.
In the method using the pressure-sensitive adhesive, for example, the pressure-sensitive adhesive is applied to the surface of the outer package 17 that contacts the battery can 15, and the outer package 17 is wound around the battery can 15 to cure the adhesive. Affixed around

Further, when ultrasonic welding is used, for example, the production efficiency can be further improved. The method using ultrasonic welding includes, for example, an insert molding process and an ultrasonic welding process.
In the insert molding step, insert molding is performed on the joined body of the battery 10 and the end case 11 by the joining pins 12 and the surface of the joined body is covered with a resin layer. The resin layer is formed on almost the entire surface of the joined body, preferably on almost the entire surface of the battery can 15 portion. As a synthetic resin constituting the resin layer, a resin having good weldability to the synthetic resin used for the outer package 17 is preferably selected as appropriate.

  In the ultrasonic welding process, the exterior body 11 is formed into a cylindrical shape, and a joined body covered with a resin layer is inserted therein. At this time, the length of the exterior body 11 in the width direction is adjusted so as to substantially match the length of the battery can 15 in the direction perpendicular to the sealing plate 16. Moreover, it adjusts so that the inner peripheral length of the cylindrical exterior body 11 may correspond with the outer peripheral length of a joining body substantially. Ultrasonic welding is performed by applying an ultrasonic wave in a state where the bonded body covered with the resin layer is inserted into the cylindrical outer body 11. Thereby, the exterior body 11 is efficiently and firmly attached around the battery can 15 of the battery 10.

  The end case 11 is a substantially plate-shaped or rectangular parallelepiped integrally molded product having substantially the same cross-sectional shape as the battery 10. The end case 11 is formed with a conduction hole 25, an insertion hole 28, an external connection window 31 and a test terminal window 32, in which an external connection terminal 26, a test connection terminal 27, a circuit board (not shown) and a safety protection element 29 parts are included.

  The conduction hole 25 is formed so as to penetrate the end case 11 in the thickness direction at substantially the center in the longitudinal direction of the end case 11. In the present embodiment, the shape of the conduction hole 25 when the conduction hole 25 is viewed from above in the vertical direction is substantially a perfect circle, but is not limited thereto, and may be an ellipse. A metal conduction rod (not shown) is attached to the conduction hole 25, and the safety protection element 29 attached to the joint surface of the end case 11 with the battery 10 and a wiring circuit provided on the circuit board surface (not shown) are electrically connected. Let In the present embodiment, the electrode terminal 19 and the safety protection element 29 are connected so as to be conductive, and the wiring circuit on the surface of the circuit board is connected to the external connection terminal 26. Therefore, the electrode terminal 19 that is the first electrode terminal. And the first external connection terminal included in the external connection terminal 26 are electrically connected.

  The conduction hole 25 can also be used as an insertion hole for mounting the joining pin 12. In this case, if the joining pin 12 is fixed so as to be in contact with the electrode 19, the electrode 19 and the external connection terminal 26 (first external connection terminal) can be made conductive through the joining pin 12. This configuration will be described more specifically with reference to FIGS.

  The insertion holes 28 are formed at positions corresponding to the recesses 18 of the battery 10 at both longitudinal ends of the end case 11 so as to penetrate the end case 11 in the thickness direction and communicate with the recesses 18. The insertion hole 28 and the recess 18 are preferably circular so that the cross-sectional shapes have substantially the same diameter, and the axis thereof coincides with the axis of the recess 18. The insertion hole 28 and the recess 18 communicating with the insertion hole 28 form a joining pin mounting hole. The joining pin 12 is attached to the joining pin mounting hole, and is fixed by a method described later.

  The inner surface of the insertion hole 28 is formed of an insulating material such as synthetic resin. This facilitates the insulation between the joining pin 12 and each component included in the end case 11. Further, the inner surface of the insertion hole 28 may be formed of a metal material. Thereby, the joining pin 12 can be fixed more firmly in the insertion hole 28. Details of this configuration will be described when the fixing method of the joining pin 12 is described.

  The external connection window 31 is formed in a triple rectangular shape in the vicinity of one insertion hole 28 on the surface of the end case 11 opposite to the joint surface with the battery 10. The external connection window 31 is provided in order to expose a part of the external connection terminal 26 on the surface of the end case 11. In the present embodiment, the external connection window 31 has a rectangular shape, but is not limited thereto, and can be formed in an arbitrary shape.

  The external connection terminal 26 is a metal part provided so as to be electrically connected to the electrode terminal 19 of the battery 10. The three external connection terminals 26 exposed from the triple external connection windows 31 are separately insulated, one or two being the first external connection terminals and the remaining being the second external connection terminals. The first external connection terminal is connected to the electrode terminal 19 which is the first electrode terminal. The second external connection terminal is connected to the battery can 15 which is a second electrode terminal. The first external connection terminal and the electrode terminal 19 are connected as described above. Further, the second external connection terminal and the battery can 15 are connected to each other via a bonding pin 12 and a wiring circuit provided on the surface of the circuit board, as will be described later. Thereby, the electrode terminal 19 or the battery can 15 and the corresponding terminal of the external device are electrically connected.

The test terminal window 32 is formed in a square shape with rounded corners in the vicinity of the other insertion hole 28 on the surface of the end case 11 opposite to the joint surface with the battery 10. The shape of the test terminal window 32 is not limited to a square shape, and can be any shape. The test terminal window 32 is provided to expose a part of the test connection terminal 27 on the surface of the end case 11. Thereby, after the battery pack 1 is assembled, a continuity test is performed using the test connection terminal 27, and it can be confirmed that the battery pack 1 operates normally. The test terminal window 32 is sealed with the insulating label 13 after the continuity test.
The test connection terminal 27 is a metal part that is electrically connected to the electrode terminal 19 of the battery 10 or the battery can 15 in the same manner as the external connection terminal 26.

  The circuit board is equipped with a charge / discharge safety circuit that controls charge / discharge of the battery 10. In addition, a wiring circuit is formed on the surface of the circuit board for electrically connecting the conductive rod and the first external connection terminal. Thereby, the electrode terminal 19 and the 1st external connection terminal are connected so that conduction | electrical_connection is possible. In addition, a wiring circuit that connects the joining pin 12 and the second external connection terminal is formed on the surface of the circuit board. Thereby, battery can 15 and the 2nd external connection terminal are connected so that conduction is possible.

  The safety protection element 29 detects heat generation associated with overcharge of the battery 10, internal short circuit, etc., and cuts off the connection between the electrode terminal 19 and the external connection terminal 26. The safety protection element 29 is disposed, for example, on the surface of the end case 11 or the circuit board facing the battery 10 and is provided so as to be electrically connected to the electrode terminal 19. The safety protection element 29 is fixed by, for example, an adhesive or welding. A recess corresponding to the shape of the safety protection element 29 may be formed on the joint surface of the end case 11 with the battery 10, and the safety protection element 29 may be attached and fixed to the recess. For example, a thermal fuse, a PTC element, or a breaker can be used as the safety protection element 29.

  The end case 11 is produced as an integrally molded product by a method including a component mounting process and a molding process, for example. In the component mounting process, components such as the external connection terminal 26, the test connection terminal 27, and the safety protection element 29 are mounted at predetermined positions on the circuit board, and a component mounting body is manufactured. In the molding process, the component mounting body obtained in the component mounting process is loaded into a predetermined mold, and molding or insert molding is performed using a synthetic resin. The end case 11 can also be produced by loading each part at a predetermined location in the mold and performing insert molding using a synthetic resin.

  Thereby, the end case 11 in which each part exists in the synthetic resin is obtained. On the joint surface of the end case 11 with the battery 10, a part of the safety protection element 29 is exposed at a position in contact with the electrode terminal 17, but the other part is covered with a synthetic resin. Therefore, the surface of the one end portion 10a (the surface of the sealing plate 16) of the battery 10 and each component housed in the end case 11 are reliably insulated. Thus, the process of arrange | positioning a fine insulated component and an insulated component can be skipped by filling gaps other than the connection location of each component with a synthetic resin. At the same time, the rigidity (mechanical strength) of the end case 11 and the battery pack 1 can be improved.

  The joining pin 12 is mounted and fixed in a joining pin mounting hole formed by the insertion hole 28 of the end case 11 and the recess 18 of the battery 10 communicating therewith. The end portion of the joining pin 12 on the end case 11 side engages with the surface of the end case 11 opposite to the surface to be joined to the battery 10 and is exposed on the surface. Thereby, the battery 10 and the end case 11 are joined.

  At the same time, the joining pin 12 is electrically connected to the battery can 15 via the inner surface of the recess 18, that is, the sealing plate 16. The joining pin 12 is in contact with a wiring circuit formed on the surface of the circuit board and capable of conducting with the second external connection terminal. With such a configuration, the battery can 15, the joining pin 12, the wiring circuit on the surface of the circuit board, and the second external connection terminal are conducted in this order. As a result, the battery can 15 serving as the second electrode terminal is electrically connected to the second external connection terminal, and the battery can 15 can be electrically connected to the corresponding terminal of the external device. That is, the joining pin 12 has a function of joining the battery 10 and the end case 11 and a function as a lead member.

  The joining pin 12 preferably includes a head portion and a shaft body portion that is formed following the head portion and has a diameter smaller than that of the head portion. The joining pin 12 may be a screw, a screw, or the like. The length and diameter of the joining pin 12 can be appropriately selected according to the design dimensions of the battery pack 1 (particularly the depth and inner diameter of the joining pin mounting hole), the material of the joining pin 12, the mechanical strength of the end case 11, and the like. . In short, it is only necessary to select a length and a diameter that can reliably contact the inner surface of the recess 18 and can reliably join the battery 10 and the end case 11 over the entire use period of the battery pack 1. For example, the length is about 1.5 to 5.0 mm and the diameter is about 0.8 to 3.0 mm. Moreover, as a material of the joining pin 12, iron, stainless steel, cast iron, soft iron etc. are mentioned, for example.

Examples of a method for fixing the joining pin 12 to the joining pin mounting hole include an adhesion method, a solder method, a resistance welding method, and an ultrasonic welding method.
According to the bonding method, first, the battery 10 and the end case 11 are overlapped. At this time, it adjusts so that the recessed part 18 of the battery 10 and the insertion hole 28 of the edge part case 11 may connect, and a joining pin mounting hole is formed. Next, a liquid conductive adhesive is injected into the recess 18 from the joining pin mounting hole. As the conductive adhesive, for example, a general adhesive obtained by adding a conductive agent such as carbon black or graphite can be used. As a general adhesive, an instantaneous adhesive mainly composed of a cyanoacrylate resin is preferable, but other adhesives can also be used. The injection amount of the conductive adhesive is preferably set so as not to overflow from the recess 18 when the joining pin 12 is mounted.

Next, the joining pin 12 is attached to the joining pin attachment hole. Since the conductive adhesive is interposed between the front end surface of the joining pin 12 located inside the recess 18 and the inner surface of the recess 18, conduction between the joining pin 12 and the battery case 15 is ensured. By solidifying this conductive adhesive, the joining pin 12 is fixed in the joining pin mounting hole, and the battery 10 and the end case 11 are joined.
According to the soldering method, the joining pin 12 can be fixed in the joining pin mounting hole in the same manner as the adhesion method except that a molten solder is used instead of the liquid conductive adhesive. When a conductive adhesive or solder is used, there is an advantage that a dimensional error between the joining pin 12 and the recess 18 can be absorbed.

  According to the resistance welding method, first, the battery case 10 and the end case 11 are overlapped to form a joining pin mounting hole in the same manner as the bonding method, and the joining pin 12 is attached to the joining pin mounting hole. In this state, one welding electrode is brought into contact with the head of the joining pin 12 (end on the end case 11 side), and the other welding electrode is brought into contact with the tip of the joining pin 12. The contact of the welding electrode to the tip of the joining pin 12 is performed, for example, by forming a working port (not shown) in the battery 10 and introducing the welding electrode into the recess 18 from the working port. Next, when a current is passed between the welding electrodes, the front end surface of the joining pin 12 and the inner surface of the recess 18 are welded. As a result, the joining pin 12 is fixed and conduction between the joining pin 12 and the battery case 15 is ensured. Note that solder may be present inside the recess 18 when a current is passed. Thereby, the joining pin 12 is fixed more firmly.

  In the resistance welding method, if the inner surface of the insertion hole 28 is made of metal, the metal on the inner surface of the insertion hole 28 is also melted and welded to the side surface of the shaft body portion of the joining pin 12. Thereby, the joining pin 12 is fixed more firmly. In order to configure the inner surface of the insertion hole 28 with a metal, for example, a metal pipe having a shape and a dimension corresponding to the insertion hole 28 may be disposed at a predetermined position during the integral molding to produce the end case 11. In addition, after the end case 11 is manufactured, only the inner surface of the insertion hole 28 may be subjected to metal plating.

  According to the ultrasonic welding method, first, the battery case 10 and the end case 11 are overlapped in the same manner as the bonding method to form a joining pin mounting hole, and the joining pin 12 is attached to the joining pin mounting hole. When an ultrasonic wave is applied to the joining pin 12 under pressure, the tip end surface of the joining pin 12 and the inner surface of the recess 18 are melted and welded. Thereby, the joining pin 12 is fixed, and the conduction between the joining pin 12 and the battery case 15 is ensured. Note that solder may be present inside the recess 18 when applying ultrasonic waves. Thereby, the joining pin 12 is fixed more firmly.

  Also in the ultrasonic welding method, it is preferable that the inner surface of the insertion hole 28 is made of metal as in the resistance welding method. By applying ultrasonic waves under pressure, the metal on the inner surface of the insertion hole 28 is melted and welded to the side surface of the shaft body portion of the joining pin 12. Thereby, the joining pin 12 is fixed more firmly.

  The insulating label 13 is a resin sheet or resin film formed to have a shape corresponding to the test terminal window 32, and seals the test terminal window 32 after the continuity test. The sealing is performed, for example, by sticking the insulating label 13 to the surface of the test terminal window 32 via an adhesive.

FIG. 6 is an exploded perspective view showing a simplified configuration of a battery pack 2 according to another embodiment of the present invention. FIG. 6A is a perspective view showing a state before the nail hook 37 is attached to the battery 35. FIG. 6B is a perspective view showing a state after the nail hook 37 is attached to the battery 35. FIG. 6C is an exploded perspective view showing a simplified configuration of the battery pack 2.
The battery pack 2 is similar to the battery pack 1, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. The battery pack 2 is characterized in that a battery 35 and an end case 38 are joined by three joining pins 12.

  The battery 35 has the same configuration as that of the battery 10 except that three recesses 18 are formed on one end face 35a (the surface of a sealing plate (not shown)). Of the three recesses 18, two recesses 18 are formed at both ends in the longitudinal direction of the sealing plate, similarly to the battery 10. The remaining one recess 18 is formed on the surface of the electrode terminal 36. The joining pin 12 mounted and fixed to the recess 18 formed on the surface of the electrode terminal 36 functions as a lead member that electrically connects the electrode terminal 36 that is the first electrode terminal and the first external connection terminal.

The end case 38 includes a molded body 39, a circuit board 40, and a test terminal (not shown), which are integrally formed by molding, insert molding, or the like.
In the molded body 39, three insertion holes 28 are formed at both ends and substantially the center in the longitudinal direction so as to correspond to the positions where the recesses 18 are formed on the one end surface 35 a of the battery 35. The insertion hole 28 is formed so as to penetrate the molded body 39 in the thickness direction and communicate with the recess 18. The cross-sectional shape of the insertion hole 28 is preferably a circular shape having a diameter substantially equal to that of the recess 18, and more preferably, the axis line thereof coincides with the axis line of the recess 18.

  Although not shown, the circuit board 40 is provided with a charge / discharge safety circuit for controlling charge / discharge of the battery pack 2, one joining pin 12 attached to the central portion of the end case 38, and a first external connection terminal. A wiring circuit that conducts, a wiring circuit that conducts the two joining pins 12 attached to both ends of the end case 38, and the second external connection terminal are mounted. In addition, the circuit board 40 has three insertion holes 41 at both ends and substantially the center in the longitudinal direction so as to correspond to the formation positions of the recesses 18 in the one end surface 35a of the battery 35 and the insertion holes 28 in the molded body 39. Is formed. The insertion hole 41 is formed so as to penetrate the circuit board 40 in the thickness direction and communicate with the recess 18 and the insertion hole 28. The cross-sectional shape of the insertion hole 41 is preferably a circle having a diameter substantially equal to that of the recess 18, and more preferably, the axis thereof coincides with the axis of the recess 18 and the insertion hole 28. The recess 18 and the insertion holes 28 and 41 form a joining pin mounting hole.

The test terminal is connected to the wiring circuit on the surface of the circuit board 40 in the end case 38. In addition, a part of the test terminal is exposed from the test terminal window 32 formed on the surface of the end case 38 opposite to the joint surface with the battery 35.
The end case 38 can be produced, for example, by integrally molding the circuit board 40 and the circuit board 40 into a mold and performing molding or insert molding. The mold is formed in a shape corresponding to the insertion hole 28 of the end case 38, the external terminal connection window 31, the test terminal window 32, and the like.

  The joining pin 12 is attached and fixed to the three joining pin attachment holes. Thereby, the battery 35 and the end case 38 are joined. In this embodiment, screws are used as the joining pins. Of the three joining pins 12, one of the joining pins 12 attached to both ends in the longitudinal direction of the end case 38 is a battery case (second electrode) (not shown) of the battery 35 through the recess 18 of the battery 35. And the other is connected to the second external connection terminal via a wiring circuit on the surface of the circuit board 40 and functions as a lead member. Another joining pin 12 is attached to the central portion in the longitudinal direction of the end case 38 and is fixed to the recess 18 formed in the electrode terminal 36 of the battery 35. Thereby, this joining pin 12 functions as a lead member which conducts the electrode terminal 36 which is the first electrode terminal and the first external connection terminal.

  Thus, the battery pack 2 is configured such that the joining pin 12 functions as a lead member that electrically connects the positive terminal, the negative terminal, and the external connection terminal. Thereby, the structure of the battery pack 2 is further simplified, the number of parts can be further reduced, and the structural strength of the battery pack 2 is also improved.

FIG. 7 is an exploded perspective view showing a simplified configuration of a battery pack 3 according to another embodiment of the present invention. FIG. 7A is a perspective view showing a state before the nail hook 37 is attached to the battery 35. FIG. 7B is a perspective view showing a state after the nail hook 37 is attached to the battery 35. FIG. 7C is an exploded perspective view showing a simplified configuration of the battery pack 3.
The battery pack 3 is similar to the battery pack 2, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. The battery pack 3 has the same configuration as that of the battery pack 2 except that it has an end case 45 instead of the end case 38.

  The end case 45 includes a molded body 39, a circuit board 40, and a safety protection element 46, which are integrally molded. The safety protection element 46 is attached from the center in the longitudinal direction of the circuit board 40 to one end on the surface of the circuit board 40 that faces the one end surface 35a of the battery 35. The safety protection element 46 includes a safety protection element main body disposed at the center in the longitudinal direction, and attachment members provided on both sides thereof. The attachment member is provided to attach the safety protection element 46 to the circuit board 40, and is mainly made of metal.

  One attachment member of the safety protection element 46 is formed with an insertion hole 47 penetrating in the thickness direction. The insertion hole 47 is formed at a position corresponding to the formation position of the recess 18 formed in the electrode terminal 36 of the battery 35, and communicates with the recess 18 and the insertion holes 28 and 41. The cross-sectional shape of the insertion hole 47 is preferably a circle having a diameter substantially equal to that of the recess 18, and more preferably the axis thereof coincides with the axis of the recess 18 and the insertion holes 28 and 41. The recess 18 and the insertion holes 28, 41, 47 form a joining pin mounting hole. The joining pin 12 is attached and fixed to the joining pin mounting hole.

  As a result, even if the safety protection element 46 is provided, the safety protection element 46 can be fixed to the circuit board 40 by the joining pin 12 that is originally used, so that an increase in the number of components can be minimized.

  The battery pack of the present invention can be suitably used as a power source for various electric and electronic devices. In particular, it is useful as a power source for portable electronic devices such as mobile phones, personal computers, portable information terminals, digital still cameras, and portable power tools.

It is a disassembled perspective view which simplifies and shows the structure of the battery pack which is one of the embodiments of the present invention. It is a perspective view which shows the external appearance of the battery pack shown in FIG. It is a top view of the battery pack shown in FIG. It is a side view of the battery pack shown in FIG. It is a longitudinal cross-sectional view which simplifies and shows the structure of the one end part of the battery contained in the battery pack shown in FIG. FIG. 5A is a longitudinal sectional view of one end of the battery and the vicinity thereof. FIG. 5B is a longitudinal sectional view of one concave portion and the vicinity thereof. FIG. 5C is a longitudinal sectional view of the electrode terminal and the vicinity thereof. It is a disassembled perspective view which simplifies and shows the manufacturing process of the battery pack which is another embodiment of this invention. FIG. 6A shows a state before the nail hook is attached to the battery. FIG. 6B shows a state after the nail hook is attached to the battery. FIG. 6C shows a simplified configuration of a battery pack according to another embodiment. It is a disassembled perspective view which simplifies and shows the structure of the battery pack which is another embodiment of this invention. FIG. 7A shows a state before the nail hook is attached to the battery. FIG. 7B shows a state after the nail hook is attached to the battery. FIG. 7C shows a simplified configuration of a battery pack according to another embodiment. It is a disassembled perspective view which simplifies and shows the structure of the conventional battery pack.

Explanation of symbols

1, 2, 3 Battery pack 10, 35 Battery 11, 38, 45 End case 12 Joint pin 15 Battery can 16 Sealing plate 17 Exterior body 18 Recess 19, 19 Electrode terminal 20 Sealing plug 21 Gasket 22 Terminal 23 Insulating member 26 External Connection terminal 27 Test terminal 28, 41, 47 Insertion hole 29 Safety protection element 30 Explosion-proof valve 31 External connection window 32 Test terminal window 37 Nail hook 39 Molded body 40 Circuit board 46 Safety protection element

Claims (10)

A battery having an end surface in which a recess is formed and the first electrode terminal is provided, and a second electrode terminal having a polarity different from that of the first electrode terminal;
An end case including an insertion hole and an external connection terminal that makes point contact with a terminal of an external device, the insertion hole is formed to penetrate the end case in the thickness direction and communicate with the recess, and the external connection terminal An end case including a first external connection terminal electrically connected to one electrode terminal and a second external connection terminal electrically connected to the second electrode terminal;
A battery pack including a joining pin that is attached and fixed to the insertion hole and the recess to join the battery and the end case and to electrically connect the second electrode terminal and the second external connection terminal.   The battery pack according to claim 1, wherein the end case is an integrally molded product made of a synthetic resin.   The battery pack according to claim 1, wherein the end case further includes at least one selected from the group consisting of a circuit board, a test connection terminal, and a safety protection element.   The battery pack according to any one of claims 1 to 3, wherein the battery is a secondary battery.   The battery pack according to any one of claims 1 to 4, wherein the battery is a lithium ion secondary battery.   The battery pack according to any one of claims 1 to 5, wherein an end portion of the joining pin is engaged with the end case.   The battery pack according to any one of claims 1 to 6, wherein the first electrode terminal is electrically connected to the first external connection terminal via a joining pin.   Furthermore, the resin layer formed in the surface of the joined body by the joining pin of a battery and an end case, and the exterior body affixed on the surface of a resin layer are described in any one of Claims 1-7 Battery pack.   The battery pack according to claim 8, wherein the resin layer is formed by loading a joined body of joining pins between the battery and the end case into a mold and performing insert molding.   The battery pack according to claim 8 or 9, wherein the exterior body is attached to the surface of the resin layer by an adhesive or ultrasonic welding.

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