JP4989113B2 - Battery pack and battery pack manufacturing method - Google Patents

Description

  The present invention relates to a secondary battery in which an insulating substrate and a protection element are connected to form a battery core pack, the battery core pack is temporarily fixed in a molding chamber of a mold, and the molding chamber is filled with a resin. A battery pack in which a resin molded part is filled between the battery and the secondary battery, and the insulating substrate and the secondary battery are connected to each other by a resin molded part molded by a mold, and a method for manufacturing the battery pack About.

  A battery pack in which an insulating substrate and a secondary battery are connected to form a battery core pack, the core pack of the battery is temporarily fixed in a molding chamber of a mold, and the core pack is inserted into a resin molding portion has been developed. In this battery pack, an insulating substrate is provided so as to face the sealing plate of the secondary battery, and a protective element such as PTC is disposed between the insulating substrate and the sealing plate to form a battery core pack. The core pack of the battery is molded by filling a resin molding portion between the insulating substrate and the sealing plate, and the insulating substrate, the protection element, and the secondary battery are connected to each other by the resin molding portion. In the battery pack having this structure, a part of the core pack of the battery is insert-molded and fixed at a fixed position in the process of molding a resin molding corresponding to the case. Therefore, since the insulating substrate, the protective element, and the secondary battery are connected in an integrated structure in the process of molding the resin molding corresponding to the exterior case, the assembly process is simplified and the mass production can be performed efficiently.

However, in this type of battery pack, the discharge pressure of the safety valve provided on the sealing plate is blocked by the molding pressure of the molten resin that molds the molded resin part, or the discharge part is filled with resin and the safety valve operates normally. There is a problem to obstruct. In order to eliminate this drawback, a battery pack has been developed in which a discharge part of a safety valve is closed with a sheet and a resin molded part is molded. (See Patent Document 1)
JP 2004-6213 A

  In the battery pack described in Patent Document 1, a resin sheet is disposed so as to cover a discharge portion of a safety valve provided on a sealing plate, and a molten resin is filled between a secondary battery and an insulating substrate. Mold the molding part. In this battery pack, the resin sheet prevents the molten resin in the resin molding part from entering the discharge part of the safety valve. Therefore, in the battery pack manufactured in this state, the discharge part of the safety valve is not blocked by the resin molding part, and the gas of the safety valve that opens can be exhausted to the outside.

  The battery pack having this structure has a drawback in that it takes a lot of time to manufacture since it is necessary to attach the resin sheet to the sealing plate and block the discharge part of the safety valve in the process of manufacturing the battery core pack. Also, if the position where the resin sheet is attached is shifted, the discharge part of the safety valve is blocked by the resin molding part, so it is necessary to adhere to the exact position of the sealing plate, and high accuracy is required for the resin sheet adhesion. . In particular, in a battery pack in which the secondary battery is a thin battery, the width of the sealing plate is narrow, and it is difficult to attach the resin sheet to an accurate position, and the displacement causes a defective product.

The present invention has been developed for the purpose of solving this drawback. An important object of the present invention is a pack battery that can be easily and easily manufactured in large quantities at a low cost by a unique structure that covers a safety valve with a protective element such as PTC without providing a dedicated part for closing the discharge part of the safety valve And providing a method for producing the battery pack.
Another important object of the present invention is to provide a battery pack capable of connecting the protective element and the secondary battery in a preferable heat conduction state, and a method for manufacturing the battery pack.

The battery pack of the present invention has the following configuration in order to achieve the aforementioned object.
The battery pack includes a secondary battery 2 having a safety valve 6 on a sealing plate 5, an insulating substrate 3 disposed opposite to the sealing plate 5 of the secondary battery 2, and the insulating substrate 3 and the secondary battery 2. The battery protective element 4 disposed between the sealing plate 5 and the sealing plate 5 of the secondary battery 2 and the insulating substrate 3 are filled and molded so that the insulating substrate 3 and the secondary battery 2 are integrated. It consists of the resin molding part 1. In the battery pack, the protective element 4 is connected to the secondary battery 2 in a structure that covers the safety valve 6 so that gas can be exhausted from the discharge part 7 in a state where the safety valve 6 provided on the sealing plate 5 is opened. In the state where the protective element 4 protects the safety valve 6, the resin molding portion 1 is molded, and the insulating substrate 3 and the secondary battery 2 are integrated.

In the battery pack of the present invention, the protective element 4 can be disposed at a position where the lead valve 16 of the protective element 4 is welded to the sealing plate 5 and covers the safety valve 6. Further, in the battery pack of the present invention, the outer can 8 of the secondary battery 2 is made of aluminum or an aluminum alloy, and the lead terminal 16 of the protective element 4 connected to the sealing plate 5 is made of a clad material made of a metal different from aluminum. Can do. Further, according to the present invention, the protection element 4 has a pair of lead terminals 16 fixed to both surfaces of the protection chip 4A, and one lead terminal 16 has a protruding portion protruding in one direction from the protection chip 4A. The protruding portion and the sealing plate are welded.

  In the battery pack of the present invention, the protection element 4 can be a temperature sensing current interrupting element that senses the heat of the secondary battery 2 and interrupts the current. Furthermore, in the battery pack of the present invention, the temperature sensing current interrupting element can be any one of PTC, breaker, and fuse.

The battery pack manufacturing method of the present invention has the following configuration in order to achieve the above-described object.
The battery pack manufacturing method includes a secondary battery 2 having a safety valve 6 on a sealing plate 5, and the secondary battery 2.
An insulating substrate 3 disposed opposite to the sealing plate 5, a battery protection element 4 disposed between the insulating substrate 3 and the sealing plate 5 of the secondary battery 2, and the secondary battery 2. The battery pack is formed between the sealing plate 5 and the insulating substrate 3, and is a method for manufacturing a battery pack including the resin molded portion 1 in which the insulating substrate 3 and the secondary battery 2 are integrated. In this manufacturing method , one lead terminal 16 of the protective element 4 is welded to the sealing plate 5, and the safety valve 6 is opened in a position covering the safety valve 6 provided on the sealing plate 5. The protective element 4 is arranged and connected to the secondary battery 2 so that the exhaust can be performed, and the protective element 4 and the insulating substrate 3 are connected to the secondary battery 2 to form the battery core pack 10. Further, the core pack 10 of the battery is temporarily fixed in the molding chamber 21 of the mold 20 for molding the resin molding portion 1, and the molding chamber 21 temporarily fixed in the core pack 10 is filled with the molten resin 24. The insulating substrate 3 and the secondary battery 2 are connected in an integrated structure so that the resin can be cured and the resin molded portion 1 can exhaust the gas from the discharge portion 7 while the safety valve 6 is open .

  The battery pack and its manufacturing method of the present invention are simple, easy and inexpensive as a unique structure for covering the safety valve with a protective element such as PTC without providing a dedicated part for closing the discharge part of the safety valve. Features that can be manufactured in large quantities are realized. Furthermore, the battery pack and the manufacturing method thereof of the present invention can connect the protection element and the secondary battery to a preferable heat conduction state, and can directly transfer the heat of the secondary battery to the protection element. For this reason, in the temperature sensing current interrupting element that operates in response to the heat of the secondary battery, it is possible to improve the safety by reacting quickly and effectively protecting the battery.

  Embodiments of the present invention will be described below with reference to the drawings. However, the examples shown below exemplify a battery pack and a manufacturing method of the battery pack for embodying the technical idea of the present invention. The battery pack manufacturing method and the manufacturing method thereof are as follows. Not specified.

  Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

  The battery pack shown in FIGS. 1 and 2 is used in a portable electronic device such as a cellular phone. In this battery pack, the secondary battery 2 is a thin rectangular battery. A battery pack in which the secondary battery 2 is a thin prismatic battery can be made compact as a whole, and is therefore suitable for a power source such as a mobile phone. However, the present invention does not specify the use of the battery pack for a mobile device such as a mobile phone. In the battery pack of FIG. 1, the core pack 10 includes one secondary battery 2, but a plurality of secondary batteries may be connected in series or in parallel to form a battery core pack.

  The battery pack of FIG. 2 includes a secondary battery 2 in which a discharge part 7 of a safety valve 6 is opened in a sealing plate 5, and an insulating substrate 3 that is disposed to face the sealing plate 5 of the secondary battery 2. The battery protection element 4 disposed between the insulating substrate 3 and the sealing plate 5 of the secondary battery 2 and the sealing plate 5 of the secondary battery 2 and the insulating substrate 3 are filled and molded for insulation. It consists of the resin molding part 1 which makes the board | substrate 3 and the secondary battery 2 an integral structure.

  The secondary battery 2 is a lithium ion secondary battery. In the secondary battery 2, an opening of an aluminum alloy exterior can 8 is sealed with an aluminum alloy sealing plate 5. The sealing plate 5 is laser-welded and airtightly connected to the opening edge of the outer can 8. The sealing plate 5 is provided with a convex electrode 9 at the center thereof, insulated from the sealing plate 5. In the secondary battery 2, the outer can 8 and the sealing plate 5 are positive, and the convex electrode 9 provided on the sealing plate 5 is negative.

  The sealing plate 5 is provided with an opening serving as a discharge part 7 at the end, and provided with a safety valve 6 that opens when the internal pressure of the battery rises to a set pressure. The illustrated safety valve 6 is formed of a thin film that is broken by the internal pressure of the battery. The thin-film safety valve 6 hermetically closes the discharge part 7 in a state where the internal pressure of the battery is lower than the set pressure. When the battery is charged / discharged in an abnormal state and the internal pressure becomes higher than the set pressure, the thin film of the safety valve 6 is destroyed. When the thin film is destroyed and the safety valve 6 is opened, the gas is discharged through the discharge portion 7 of the sealing plate 5 and the internal pressure of the battery is lowered. The secondary battery 2 including the safety valve 6 having this structure can prevent the outer can 8 and the sealing plate 5 from being destroyed due to the internal pressure of the battery becoming higher than the set pressure. Safety valves are all structures that open at a set pressure instead of a thin film.For example, the valve body to be opened and closed is pressed with an elastic body and closed when the internal pressure of the battery is lower than the set pressure. It can also be set as the structure which opens when it becomes higher than this.

  The insulating substrate 3 fixes an electronic component 11 of a protection circuit that charges and discharges while protecting the battery to the lower surface. The protection circuit mounted on the insulating substrate 3 cuts off the current when an overcurrent flows through the battery, and cuts off the discharge current when the voltage of the discharging battery drops to a set voltage, and further charges the battery. It is a circuit such as a protection function that cuts off the charging current when the voltage of the battery rises to the set voltage. Furthermore, the protection element 4 can detect the temperature of the battery, cut off the current, and prevent harmful effects due to the temperature of the battery. The protection circuit mounted on the insulating substrate 3 is designed to be optimal for the type of secondary battery. The secondary battery 2 of the pack battery is not limited to a lithium ion secondary battery, and a nickel-hydrogen battery or a nickel cadmium battery can also be used. The battery pack incorporating these batteries can simplify the protection circuit mounted on the insulating substrate 3. Moreover, it is also possible to charge and discharge the battery while protecting the battery with only the protective element 4 connected in series with the battery without mounting an electronic component that realizes a protection circuit on the insulating substrate.

  The insulating substrate 3 has an output terminal 12 fixed on the upper surface. As shown in FIG. 1, the output terminal 12 is exposed to the outside from an electrode window 13 that is molded and formed in the resin molding portion 1. The insulating substrate 3 shown in the figure is connected to the protective element 4 having one end connected to the convex electrode 9 of the battery via the connection lead plate 14 and the other end connected to the sealing plate 5 via another connection lead plate 15. It is connected. The insulating substrate 3 is inserted into the resin molding part 1 so as not to protrude from the resin molding part 1 to be molded. The insulating substrate 3 has a width narrower than that of the sealing plate 5 and a length shorter than the entire length of the sealing plate 5. The insulating substrate 3 shown in the figure is connected to the secondary battery 2 via the connection lead plates 14 and 15 in a posture facing the sealing plate 5 as about half the length of the sealing plate 5.

  The protection element 4 is a temperature sensing current interruption element that senses heat of the secondary battery 2 and interrupts the current. Since the protection element 4 of the temperature sensing current interruption element interrupts the current when the temperature of the battery becomes abnormally high, the battery can be protected from a high temperature failure and the pack battery can be charged and discharged safely. The protection element 4 of the temperature sensing current interrupting element is a PTC that substantially interrupts the battery current because the electrical resistance is significantly increased when the temperature is higher than the set temperature. However, a temperature sensing current interrupting element such as a fuse or a breaker can be used as the protection element of the temperature sensing current interrupting element instead of the PTC.

  The protection element 4 is shown in FIG. The protection element 4 is electrically connected to the protection chip 4A by fixing lead terminals 16 on both surfaces of the protection chip 4A. The protective chip 4A is a rectangular parallelepiped, and in the drawing, the first lead terminal 16A is provided on the upper surface, and the second lead terminal 16B is provided on the lower surface. The first lead terminal 16A includes a first connection layer 16a connected to the upper surface of the protection chip 4A, and a lead terminal plate 18 connected to the first connection layer 16a. The first lead terminal 16A of the protection element 4 is connected to the insulating substrate 3 through the connection lead plate 15 by connecting the connection lead plate 15 to the upper surface of the lead terminal plate 18 by a method such as spot welding. The first connection layer 16a is a metal foil having the same outer shape as the protective chip 4A, and is vapor-deposited and connected to the upper surface of the protective chip 4A. The lead terminal plate 18 is a metal plate and is reflowed and connected to the first connection layer 16a. The lead terminal plate 18 has a predetermined thickness so as to have a sufficient heat capacity that can protect the protective chip 4A from heat when the connection lead plate 15 is joined by spot welding or the like. For example, a nickel plate having a thickness of 0.3 mm can be used for the lead terminal plate 18.

  The second lead terminal 16B includes a second connection layer 16b connected to the lower surface of the protection chip 4A and a lead terminal plate 17 connected to the second connection layer 16b. The second lead terminal 16B of the protection element 4 is connected to the secondary battery 2 with the lead terminal plate 17 connected to the sealing plate 5. The lead terminal plate 17 is provided with a connecting portion 17A that protrudes laterally from the protective chip 4A and is welded to the sealing plate 5. The second connection layer 16b is a metal foil having the same outer shape as the protective chip 4A, and is vapor-deposited and connected to the lower surface of the protective chip 4A. The lead terminal plate 17 is a clad material in which the surface connected to the sealing plate 5 is aluminum and the other surface is a metal different from aluminum such as nickel. The lead terminal plate 17 is reflowed and connected to the second connection layer 16b. The lead terminal plate 17 which is a clad material can be stably and reliably connected to the sealing plate 5 by laser welding or resistance welding. However, the lead terminal plate can be connected to the sealing plate by ultrasonic welding. Ultrasonic welding can weld dissimilar metals. Therefore, the lead terminal plate to be ultrasonically welded does not necessarily have to be a clad material, and may be a nickel plate or a copper plate, for example.

  The protection element 4 is connected to the sealing plate 5 with a structure that covers the safety valve 6. The protection element 4 in FIG. 2 is a discharge portion 7 of the safety valve 6 and is connected to the sealing plate 5 so as to close the opening portion opened in the sealing plate 5. Therefore, the protection element 4 has a larger outer shape than the discharge part 7 of the safety valve 6. The protection element 4 is fixed at a position where the lead terminal plate 17 of the second lead terminal 16B is connected to the sealing plate 5 and the discharge portion 7 of the safety valve 6 is closed. The protection element 4 is connected to the sealing plate 5 so as to close the exhaust part 7 of the safety valve 6 but not seal it so that gas can be exhausted from the exhaust part 7 in a state where the safety valve 6 is opened. Furthermore, as shown in FIG. 4, the secondary battery including the safety valve 46 that closes the discharge portion 47 opened in the sealing plate 45 with a thin film on the outer surface of the sealing plate 45 is positioned above the discharge portion 47. The protective element 4 is connected to a position that covers the safety valve 46 that closes the discharge portion 47. This protective element 4 is also connected to the sealing plate 45 so that the gas can be exhausted from the discharge part 47 in a state where the safety valve 46 is opened.

In the battery pack, the protective element 4 is connected to the secondary battery 2, the insulating substrate 3 is connected to the protective element 4 via the connection lead plate 15, and the insulating substrate 3 is connected to the secondary battery 2 via another connection lead plate 14. It connects with the convex electrode 9, and it is set as the core pack 10 of a battery. A battery core pack 10 is formed by connecting a protection element 4 and an insulating substrate 3 to a secondary battery 2. The battery core pack 10 is assembled in the following steps.
(1) The protective element 4 is disposed at a position covering the safety valve 6 provided on the sealing plate 5, and the lead terminal plate 17 of the second lead terminal 16 </ b> B is laser-welded and connected to the sealing plate 5.
(2) Two connecting lead plates 14 and 15 are connected to the insulating substrate 3 by a method such as soldering, or two connecting lead plates are soldered to the insulating substrate and the two connecting lead plates are spot welded or the like. Connect with
(3) One connection lead plate 15 is spot welded to the first lead terminal 16A of the protective element 4 and the other connection lead plate 14 is spot welded to the convex electrode 9 of the secondary battery 2. Connecting.
(4) The connecting lead plates 14 and 15 are bent in a U shape so that the insulating substrate 3 is in a posture parallel to the sealing plate 5.

  As shown in FIG. 5, the battery core pack 10 is temporarily fixed in the molding chamber 21 of the mold 20 to mold the resin molding portion 1. The resin molding part 1 is molded with a molten resin filled in the molding chamber 21 of the mold 20. The resin molding part 1 is filled in the gap between the insulating substrate 3 and the sealing plate 5 and molded with the protective element 4 inserted, and connects the secondary battery 2, the insulating substrate 3, and the protective element 4 in an integrated structure. . In the battery pack of FIG. 2, the upper surface of the insulating substrate 3 is covered with the resin molding portion 1 that opens the electrode window 13. The electrode window 13 is opened at a position where the output terminal 12 is exposed to the outside. Further, the battery pack shown in the figure has a molded resin part 1 formed on the bottom surface of the secondary battery 2 on the side opposite to the sealing plate 5. The molded battery 1 on the bottom surface and the molded resin part 1 on the sealing plate 5 side are provided. Are connected through a connecting portion provided along the side edge of the secondary battery 2 to form an integrated structure. The resin molded portion 1 has a feature that the sealing plate 5 side and the bottom surface side are connected by a connecting portion so that both can be securely fixed to the secondary battery 2.

The resin molding part 1 is molded in the following steps.
(1) The core pack 10 is temporarily fixed in the molding chamber 21 of the mold 20. In order to hold the insulating substrate 3 and the secondary battery 2 in a fixed position in the temporarily fixed state, a part of the outer peripheral edge of the insulating substrate 3 is supported by a locking portion 22 provided in the mold 20, and the secondary battery 2 is locally supported and supported by a support portion 23 that supports a fixed position. In this state, the secondary battery 2 and the insulating substrate 3 are held at fixed positions in the molding chamber 21.
(2) The molding chamber 21 is closed in a state where the core pack 10 is temporarily fixed, and the closed molding chamber 21 is filled with the molten resin 24. As the molten resin 24, a resin such as urethane that is in a molten state at a low temperature is used. The filled molten resin 24 is filled between the insulating substrate 3 and the secondary battery 2, filled so as to embed the protective element 4, and further filled into the gap of the molding chamber 21. At this time, since the safety valve 6 of the sealing plate 5 is covered and protected by the protection element 4, the molten resin 24 is prevented from flowing into the discharge portion 7 of the safety valve 6 and being blocked.
(3) After the molten resin 24 is cured, the die 20 is opened and the completed battery pack is taken out from the molding chamber 21.

1 is a perspective view of a battery pack according to an embodiment of the present invention. It is a partial cross section front view of the battery pack shown in FIG. It is an expansion perspective view of the protection element incorporated in the battery pack shown in FIG. It is an exploded sectional view of a battery pack according to another embodiment of the present invention. It is sectional drawing which shows the state which shape | molds the resin molding part of the battery pack shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Resin molding part 2 ... Secondary battery 3 ... Insulating substrate 4 ... Protection element 4A ... Protection chip 5 ... Sealing plate 6 ... Safety valve 7 ... Discharge part 8 ... Exterior can 9 ... Convex electrode 10 ... Core pack 11 ... Electronic component DESCRIPTION OF SYMBOLS 12 ... Output terminal 13 ... Electrode window 14 ... Connection lead board 15 ... Connection lead board 16 ... Lead terminal 16A ... 1st lead terminal
16B ... Second lead terminal
16a ... 1st connection layer
16b ... 1st connection layer 17 ... Lead terminal board 17A ... Connection part 18 ... Lead terminal board 20 ... Mold 21 ... Molding chamber 22 ... Locking part 23 ... Support part 24 ... Molten resin 45 ... Sealing plate 46 ... Safety valve 47 ... discharge section

Claims (6)

A secondary battery (2) having a safety valve (6) on the sealing plate (5), an insulating substrate (3) disposed opposite the sealing plate (5) of the secondary battery (2), and this A battery protection element (4) disposed between the insulating substrate (3) and the sealing plate (5) of the secondary battery (2), and a sealing plate (5) of the secondary battery (2) A battery pack comprising a resin molded part (1) that is integrally formed with an insulating substrate (3) and a secondary battery (2) that is filled and molded between the insulating substrate (3),
The protective element (4) is connected to the secondary battery (2) with a structure covering the safety valve (6) provided on the sealing plate (5), and the protective element (4) protects the safety valve (6). Then, by molding the resin molding part (1), the insulating substrate (3) and the secondary battery (2) are made into an integral structure,
The safety valve (6) is welded to the sealing plate (5), and the safety valve (6) is opened so that the gas can be exhausted from the discharge part (7). 6) A battery pack in which a protective element (4) is arranged in a position to cover. The protective element (4) has a pair of lead terminals (16) fixed on both sides of the protective chip (4A),
The battery pack according to claim 1, wherein one lead terminal (16) has a protruding portion protruding in one direction from the protective chip (4A), and the protruding portion and the sealing plate are welded. .   The outer can (8) of the secondary battery (2) is made of aluminum or an aluminum alloy, and the lead terminal (16) of the protective element (4) connected to the sealing plate (5) is a clad material made of a metal different from aluminum. The battery pack according to claim 1 or 2.   The battery pack according to claim 1, wherein the protection element (4) is a temperature sensing current interruption element that senses heat of the secondary battery (2) and interrupts the current.   The battery pack according to claim 4, wherein the temperature sensing current interrupting element is any one of a PTC, a breaker, and a fuse. A secondary battery (2) having a safety valve (6) on the sealing plate (5), an insulating substrate (3) disposed opposite the sealing plate (5) of the secondary battery (2), and this A battery protection element (4) disposed between the insulating substrate (3) and the sealing plate (5) of the secondary battery (2), and a sealing plate (5) of the secondary battery (2) A method for producing a battery pack comprising a resin molded part (1) that is integrally molded between an insulating substrate (3) and a secondary battery (2) that is filled and molded between the insulating substrate (3),
A state in which the safety valve (6) is opened at a position covering the safety valve (6) provided on the sealing plate (5) by welding one lead terminal (16) of the protective element (4) to the sealing plate (5). The protective element (4) is arranged and connected to the secondary battery (2) so that the gas can be exhausted from the discharge part (7) , and the protective element (4) and the insulating substrate (3) are connected to the secondary battery. The battery core pack (10) is connected to the battery (2), and the battery core pack (10) is temporarily fixed in the molding chamber (21) of the mold (20) for molding the resin molding part (1). In the state where the molding chamber (21) temporarily fixed in the core pack (10) is filled with the molten resin, the filled resin is cured, and the safety valve (6) is opened in the resin molding portion (1). A method of manufacturing a battery pack in which the insulating substrate (3) and the secondary battery (2) are connected in an integrated structure so that the gas can be exhausted from the discharge part (7) .

Images