JP3221872B2 - Secondary battery with battery protection circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a secondary battery such as a lithium ion secondary battery, which is provided with a battery protection circuit integrally with the secondary battery to provide a function of protecting the battery itself from overcharge and overdischarge. More particularly, the present invention relates to a secondary battery including a battery protection circuit adapted to be applied to a small and flat secondary battery.

[0002]

2. Description of the Related Art Secondary batteries are used to prevent battery damage due to abnormal use such as short-circuiting of battery peripheral circuits, short-circuiting between positive and negative electrodes, and overcharging and overdischarging of equipment using the secondary batteries. Protection function is provided. These include PTC elements that prevent excessive discharge current due to short circuits, etc., and current cutoff valves that release the internal pressure by interrupting the current-carrying circuit due to an abnormal rise in battery internal pressure due to overcharging. It is a well-known function to be equipped. In addition, a lithium ion secondary battery is provided with a battery protection circuit to prevent overcharging, overdischarging, and the like, and this battery protection circuit generally has a battery protection circuit in the form of a battery pack together with the lithium ion secondary battery. The formed circuit board is housed in a pack case and integrated. It is well-known that such a battery pack in which a secondary battery and a battery protection circuit are housed and integrated in a pack case is often used as a battery power supply device of a portable device such as a mobile phone or a portable computer. By the way.

[0003] The battery protection circuit can have functions of preventing overcharge and overdischarge, shutting off excessive current, monitoring the battery temperature, and the like, and can be integrated with the secondary battery itself. If possible, a secondary battery having a battery protection circuit can be formed without forming a battery pack, and a highly versatile secondary battery can be provided.

[0004]

However, when a battery protection circuit is integrated with a secondary battery, it is a problem to configure the secondary battery without impairing the form of the secondary battery and suppressing an increase in external dimensions. In particular, in the case of a small flat secondary battery, in order to integrate the battery protection circuit into the battery, it is difficult to integrate the battery protection circuit while suppressing the increase in external dimensions due to a small arrangement space.

[0005] In addition, in the case of a small flat secondary battery, there is little space for providing the above-mentioned PTC element and the current cutoff valve, and when these are provided, there is a problem that the battery capacity is reduced due to a decrease in the number of power generation elements. Is provided outside the secondary battery as part of the battery protection circuit, and the function of the current cutoff valve must be delegated to the battery protection circuit. However, when the PTC element is provided as a part of the battery protection circuit, an increase in volume when the battery protection circuit is integrated with the secondary battery is unavoidable, and it is difficult to achieve the purpose of suppressing an increase in external dimensions. Further, in a normal battery protection circuit, the valve body is broken by a battery internal pressure accompanying gas generated in an overcharge region exceeding an overcharge protection voltage set in the circuit, and functions as a current cutoff valve that cuts off current. I couldn't do that.

An object of the present invention is to provide a compact structure applicable to a flat type secondary battery so as to suppress an increase in the external dimensions of the secondary battery, and to improve the function of a battery protection circuit to provide a PTC element and a current supply. It is an object of the present invention to provide a secondary battery having a battery protection circuit which enables battery protection by a circuit configuration without providing a shut-off valve and which can be used in almost the same size as a single battery without requiring a battery pack.

[0007]

Means for Solving the Problems A first invention of the present application for achieving the above object is a battery can in which a power generating element is housed in a bottomed cylindrical container, and a closure for closing an open end of the battery can. A battery protection circuit for protecting the secondary battery from overcharging, overdischarging, etc., is integrated with a secondary battery in which a positive electrode or a negative electrode is respectively set to a protruding terminal provided insulated from the battery can. A secondary battery provided with a battery protection circuit provided in a fixed manner, wherein a circuit board on which a battery protection circuit and a plurality of input / output terminals are formed is disposed on the sealing portion, and the projecting terminal and the battery can are connected to each other. Each of the intermediate completed products is connected to the input / output terminal via a battery protection circuit to integrate the secondary battery and the circuit board, and the intermediate completed product is formed into a bottomed cylindrical shape by resin molding. An opening is provided on the bottom surface at a position corresponding to the input / output terminal. A battery protection circuit for a secondary battery, characterized by being inserted into a formed outer case having rigidity, closing an open end with a sealing piece, and enclosing an intermediate completed product in the outer case. The intermediate completed product with the circuit board integrally formed is enclosed in an outer case, and the input / output terminals formed on the circuit board are exposed from the opening of the outer case to provide a compact battery protection circuit. A secondary battery is configured.

According to a second aspect of the present invention, there is provided a battery can in which a power generating element is housed in a cylindrical container having a bottom, and a sealing portion for sealing an open end of the battery can insulated from the battery can. A battery protection circuit integrally provided with a battery protection circuit for protecting the secondary battery from overcharging, overdischarging, etc., with a protruding terminal and a positive electrode or a negative electrode set respectively. A secondary battery, wherein on the side of the sealing portion, a connection plate joined to the protruding terminal, a circuit board on which a battery protection circuit and a plurality of input / output terminals are formed, and a seating surface of the circuit board are formed. A spacer for separating the secondary battery is provided, and the lead plate and the connection plate joined to the battery can are connected to predetermined positions of the circuit board, respectively. And the secondary battery and the battery protection circuit The positive and negative electrodes of the secondary battery are electrically connected to each other to form an intermediate completed product connected to the input / output terminal via a battery protection circuit, and this intermediate completed product is formed into a bottomed cylindrical shape by resin molding. And inserted into a rigid outer case having an opening formed at a position corresponding to the input / output terminal on the bottom surface, closing the open end with a sealing piece, and sealing the intermediate product in the outer case. The circuit board that constitutes the battery protection circuit is disposed on the sealing portion of the secondary battery via a spacer, so that the height of the secondary battery is prevented from increasing and the battery protection circuit is reduced. Can be connected to a secondary battery, and this is sealed in an outer case provided with an opening at a position corresponding to the input / output terminal, thereby forming a compact secondary battery with an integrated battery protection circuit. You.

In each of the above structures, the outer case for accommodating the secondary battery having an oval cross section has an outer shape of a substantially rectangular cross section and an inner shape of the outer shape of the secondary battery. By forming a substantially oblong shape corresponding to
A secondary battery provided with a battery protection circuit can be configured in a rectangular parallelepiped shape that can be easily loaded into a device, and can also increase the strength of an outer case.

In the outer case, a sealing piece is formed on the open end side of the bottomed rectangular cylindrical shape, the sealing piece extending on the long side, and the sealing piece is bent inward by a hot press and the opposing portion is melted. By closing the open end, the intermediate completed product can be sealed in the outer case, and the intermediate completed product can be sealed by the one-piece outer case.

It is preferable that the sealing piece has an uneven shape formed on each of the opposed long sides of the rectangular open end so that the unevenness is fitted to each other when bent. Thus, the sealing strength can be improved.

[0012] Further, the sealing piece is formed with a thick molten portion, so that a sufficient amount of resin to be melted can be obtained.
Reliable welding is possible.

The sealing piece is formed in such a shape that a gap is formed between the opposing pieces when the sealing piece is bent, so that the opposing piece does not overlap due to a bending error, and the molten resin is removed from the gap. It can penetrate inside and fill gaps due to dimensional errors of the intermediate finished product to absorb the errors.

Further, by providing the projection on the inner surface side of the sealing piece, the gap due to the dimensional error of the intermediate completed product is filled with the projection, so that occurrence of rattling can be prevented.

In the outer case, a sealing piece having a side peripheral portion formed on the open end side of the bottomed square cylindrical shape is formed, and after inserting an intermediate completed product, the sealing piece is inwardly pressed by a hot press. The open end can be closed by melting the extended sealing piece inside and filling the open end side of the inserted intermediate product. Even when a height error occurs in the intermediate completed product, the outer case is finished to have a constant height by a change in the amount of the molten resin flowing into the gap in the outer case.

Further, by arranging the plurality of input / output terminals asymmetrically, reverse loading of the device can be prevented.

[0017]

Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
The embodiment described below is an example embodying the present invention, and does not limit the technical scope of the present invention.

In the embodiment described below, a flat lithium ion secondary battery as shown in FIG. 3 is integrated with a circuit board having a battery protection circuit for protecting the secondary battery from overcharge, overdischarge, and the like. As shown in FIG. 1, the secondary battery is provided with a battery protection circuit without damaging the form of the secondary battery.

In FIG. 1, a secondary battery provided with a battery protection circuit according to the present embodiment accommodates a secondary battery 1 and a circuit board 9 constituting the battery protection circuit in an outer case 7 formed by resin molding. The positive terminal 4, the negative terminal 5, and the temperature detecting terminal 6 are exposed on one end surface to the outside.

FIG. 2 is an exploded view showing the internal structure of the secondary battery 1. A positive electrode input / output terminal (protruding terminal) of the secondary battery 1 A) a connection plate 11 joined to 25), a spacer 12 provided on the secondary battery 1 to provide a seating surface for the circuit board 9,
A circuit board 9, which constitutes a battery protection circuit and has a positive terminal 4, a negative terminal 5, and a temperature detection terminal 6, is provided. A base 10 b is joined to the bottom of the secondary battery 1 and to the bottom of the secondary battery 1. A lead plate 10 is provided to extend the lead portion 10a to the sealing portion side.

As shown in FIG. 3, the secondary battery 1 includes a power generation element 3 in a battery can 31 formed in a bottomed cylindrical shape having an oval cross section.
3 and a sealing portion provided with a gasket 35, a sealing plate 32, and an electrode cap 34 at the open end of the battery can 31.
The battery can 31 is formed in a small and flat shape in which the opening end is sealed by fixing the sealing portion by crimping processing in which the opening end of the battery can 31 is bent inward. Power generation element 33
The positive plate constituting the battery can 31
Is connected to the electrode cap 34 which is insulated from the electrode cap 34, and the central protrusion thereof serves as the positive electrode input / output terminal 25 of the secondary battery 1. The negative electrode plate constituting the power generating element 33 is connected to the battery can 31, and the battery can 31 serves as a negative input / output terminal of the secondary battery 1.

The positive electrode input / output terminal 25 of the secondary battery 1
The base 11b of the connection plate 11 formed in an L shape is joined. The base 10b of the lead plate 10 is joined to the bottom surface of the battery can 31, and the lead portion 10a extends along the side surface of the battery can 31 toward the sealing portion.

Further, a spacer 12 formed as shown in FIG. 4 is attached to the sealing portion side of the secondary battery 1.
As shown in FIG. 4B, on the lower surface (the secondary battery 1 side) of the spacer 12, a positive electrode input / output terminal 25 formed in an oval shape is provided.
A pair of positioning portions 37 are formed in contact with the side surfaces in the longitudinal direction, and are arranged on the sealing portion so as to be fitted to the positive electrode input / output terminals 25, whereby the spacer 12 is positioned on the secondary battery 1. Mated.

The connection plate through hole 38 opened between the pair of positioning portions 37 allows the lead portion 11a of the connection plate 11 joined to the positive electrode input / output terminal 25 to penetrate the upper surface. The spacer 12 forms a seat surface insulated from the secondary battery 1, and the seat surface has openings 36 a and 36 b for housing electronic components mounted on the sealing portion side of the circuit board 9. When the circuit board 9 is disposed thereon, the electronic components mounted on the sealing portion side are accommodated in the openings 36a and 36b.
The thickness is added to the secondary battery 1 only at the height obtained by adding the thickness of the battery, and the increase in height due to the provision of the battery protection circuit is suppressed.

FIG. 5 is a perspective view of a circuit pattern formed on the front and back surfaces of the circuit board 9 and electronic components mounted on the circuit pattern. The battery protection circuit shown in FIG. And an output terminal. As shown in FIG.
On the back side (b) of the circuit board 9, IC components 21 and 22 are provided.
A battery protection circuit on which the chip component 26 is mounted is formed. On the front side (a), the plus terminal 4, the minus terminal 5, the temperature detection terminal 6, and the connection plate conductor pattern 15 for connecting the connection plate 11. A lead plate conductor pattern 16 for connecting the lead plate 10 is formed. The circuit patterns formed on both sides are through holes 3
Connected by 0. The lead portion 11a of the connection plate 11 is passed through the lead through hole 20 formed in the circuit board 9, and the lead portion 11a is bent onto the connection plate conductor pattern 15 and soldered. Further, the lead portion 10a of the lead plate 10 is passed through the lead plate through recess 29 formed at the end of the circuit board 9, and is bent and soldered onto the lead plate conductor pattern 16. By soldering the connection plate 11 and the lead plate 10, the secondary battery 1 and the circuit board 9 are electrically connected, and the circuit board 9 is fixed on the secondary battery 1.

The battery protection circuit shown in FIG. 6 is a main control circuit IC for protecting the secondary battery 1 from overcharge, overdischarge and overcurrent.
When the voltage in the state of overcharge, overdischarge and overcurrent is detected, the switching element incorporated in the IC is controlled to the off state and turned off until a predetermined release voltage is detected by the hysteresis operation. The state is maintained, and the input / output circuit of the secondary battery 1 is shut off to prevent the secondary battery 1 from being overcharged, overdischarged, and overcurrent. Further, control is performed such that energization is enabled in the discharging direction when the input / output circuit is interrupted due to overcharging, and energization is enabled in the charging direction when the input / output circuit is interrupted due to overdischarging. In addition to the main control circuit IC22, a sub-control circuit IC21 for protecting the secondary battery 1 from overcharge is provided. The sub-control circuit IC21 normally controls the switching element incorporated in the IC to be in an on state to keep the input / output circuit in a conductive state, and when the operation of preventing overcharge is not performed due to an abnormal operation of the main control circuit IC22. ,
The progress of the overcharge state is detected, the switching element is controlled to the off state, the input / output circuit is cut off, the off state is maintained until a predetermined release voltage is detected by the hysteresis operation, and the secondary battery 1 is overcharged. To prevent damage due to the progress of the work. With this configuration, the secondary battery 1 is doubly protected from overcharge. In particular, the secondary battery 1 that is significantly damaged by overcharge can be protected by the battery protection circuit. Therefore, a current cutoff valve or a PTC (Pos) conventionally provided in the battery to protect the battery.
active Temperature Coeffic
i) can be eliminated, which is a suitable means in the case of the small and thin secondary battery 1 applied to the present embodiment. In other words, it is difficult to obtain a space for providing a current cutoff valve and a PTC in a small or thin battery, and by providing these, the volume of the positive and negative electrodes serving as power generation elements is reduced, and the battery performance is reduced due to a reduction in battery capacity. The problem of being unable to obtain is eliminated. Also, PT
If C is configured as a part of the battery protection circuit, the space occupied by the battery protection circuit increases, which hinders miniaturization. However, the battery protection circuit of this configuration can configure a battery protection circuit without PTC.

As shown in FIG. 5A, the plus terminal 4 is provided on the plus terminal conductor pattern 4a formed on the front side of the circuit board 9, and the minus terminal 5 is provided on the minus terminal conductor pattern 5a. The temperature detection terminal 6 is joined onto the detection terminal conductor pattern 6a. By using a copper-nickel alloy plate or a clad material of the copper-nickel alloy and stainless steel, these terminals are excellent in conductivity, bonding property, and corrosion resistance. Also, each conductor pattern can be plated with gold and used as a terminal without joining a plate material as a terminal.

By attaching the circuit board 9 to the secondary battery 1 as described above, an intermediate completed product 50 in which the secondary battery 1 and the circuit board 9 are integrated is formed as shown in FIG. The intermediate completed product 50 is sealed in an outer case 7 formed as shown in FIG. 8, and a secondary battery having a battery protection circuit in a form as shown in FIG. 1 is completed.

In FIG. 8, the outer case 7 has a plus terminal window 4c at a position corresponding to the plus terminal 4 provided on the circuit board 9 and a position corresponding to the minus terminal 5 on the bottom surface formed in a rectangular tube shape with a bottom. The temperature detecting terminal window 6c is opened at a position corresponding to the minus terminal window 5c and the temperature detecting terminal 6, respectively, and sealing pieces 13, 13 for closing the open end after accommodating the intermediate completed product 50 at the open end are formed. Have been. As shown in FIG. 8D, the cross-sectional shape of the outer case 7 has a substantially oval shape and an outer shape of a square corresponding to the shape of the secondary battery 1 in which the inner surface of the cross-sectional shape is formed into an oval shape. The secondary battery 1 which is formed in a rectangular shape provided with a round shape and has an oval cross section is converted into a shape that is not wasted for loading into a device.

The sealing pieces 13 are inserted into the circuit board 9 from the open end of the outer case 7 in the state shown in FIG. As shown in FIG. 9 (c), it is bent inward by a hot press mold.
As shown in FIG.
3 are welded / formed, and the intermediate completed product 50 is sealed in the outer case 7. The end of the sealing piece 13 is formed to be thick as shown in the drawing, so that the resin is melted and the sealing piece 1 is formed.
The gap between the opposing surfaces 3 and 13 can be filled, and the amount of resin that can provide sufficient welding strength can be secured.

As shown in FIG. 10, the sealing piece 13 may be formed in a comb shape in which the opposing pieces fit together. Further, the opposing sealing pieces 13 and 13 are formed such that a gap is formed between the opposing sealing pieces when they are bent, so that the gap is filled by melting. If both or one of the comb-shaped portions 14 of the sealing pieces 13 and 13 is formed thicker than the other portion, in order to fill this gap to enable reliable welding, a sufficient amount of resin to be melted can be obtained. Become like

The intermediate finished product 50 accommodated in the outer case 7 varies in height due to dimensional errors and assembly errors of its components, and when the intermediate product 50 is smaller than a specified size, the intermediate finished product 50 has However, by causing the molten resin to enter the gap through the gap between the outer case 7 and the intermediate product 50, the gap that causes the gap is filled, and the dimensional variation is absorbed. You. Also, as shown in FIGS. 9 and 10, if the projections 18 are formed inside the sealing piece 13, the gap is filled when the size is smaller than the specified size of the intermediate completed product 50. Since the height is reduced by melting, variations in the dimensions of the intermediate completed product 50 can be more effectively absorbed.

The open end of the outer case 7 is sealed by extending the four sides of the side peripheral portion and melting the same by hot pressing so that the outer case 7 is at a predetermined height and the open end is closed. It can also be molded. According to this sealing means, even when the height of the intermediate completed product 50 varies as described above, it is possible to perform sealing molding to absorb the variation. That is, when the height of the intermediate completed product 50 is in the plus direction from the specified value, the pressure at the time of hot pressing increases, so that the excess amount of the molten resin is filled in the gap between the outer case 7 and the intermediate completed product 50. After flowing in, the open end is sealed with a thin resin layer. On the other hand, when the height of the intermediate completed product 50 is in the minus direction from the specified value, the pressure at the time of hot pressing is small, the amount of the molten resin flowing into the gap is small, and the open end is formed by sealing with a thick resin. You.

In the secondary battery provided with the battery protection circuit configured as described above, as shown in FIG. 1, the battery protection circuit is provided by only slightly increasing the height of the secondary battery 1, and
When set in a device in this state, the device itself has a battery protection function and becomes a highly reliable battery power source. In addition, a plus terminal 4, a minus terminal 5, and a temperature detection terminal 6
Since the are arranged asymmetrically in the left and right direction, reverse loading of the device can be prevented.

The flat secondary battery 1 is mainly used for a battery power source of a small portable electronic device, and an increase in the thickness impairs the advantages of the flat secondary battery. A battery protection circuit can be provided without increasing the thickness of the battery, and a secondary battery with a battery protection circuit that is smaller and lighter than a battery pack is configured. , Which contributes to weight reduction.

Further, the secondary battery 10 applied to the present embodiment
Shows an example of a lithium ion secondary battery in which a positive electrode input / output terminal 25 is provided in a sealing portion and a battery can 26 is used as a negative electrode input / output terminal. Needless to say, a battery can be similarly implemented by changing the connection.

[0037]

As described above, according to the present invention, since the battery protection circuit is integrally formed with the secondary battery, it can be used as if only the battery is loaded in the device without providing a battery pack. This can contribute to miniaturization and weight reduction of equipment using a secondary battery as a power supply. In addition, by improving the function of the battery protection circuit, the secondary battery can be protected from overcharge, overdischarge, overcurrent, etc. without providing a PTC element or a current cutoff valve, and can be reliably used without reducing the capacity of the secondary battery. A highly reliable battery protection function can be configured compactly.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a secondary battery with a battery protection device according to an embodiment.

FIG. 2 is a perspective view showing an assembled structure by disassembling an internal structure.

FIGS. 3A and 3B show a configuration of a secondary battery; FIG.
Is a sectional view.

FIGS. 4A and 4B show the structure of a spacer, FIG.
Is a plan view of the lower surface side, and (c) is a cross-sectional view taken along line AA.

FIGS. 5A and 5B show the configuration of the circuit board, FIG.
Is a plan view of the back side.

FIG. 6 is a circuit diagram showing an electrical configuration of a secondary battery including a battery protection circuit.

FIG. 7A is a plan view showing the configuration of an intermediate completed product.
(B) is a side view.

8A is a plan view of a bottom side of the outer case, and FIG.
Is a side view, (c) is a plan view of the open end side, (d) is BB
FIG.

FIGS. 9A and 9B are perspective views showing the sealing of the open end of the outer case, wherein FIG. 9A is an initial state, FIG. 9B is a bent state, and FIG.

10A is a plan view showing another embodiment of the sealing piece, FIG.
(B) and (c) are side views, and (d) is a plan view showing a bent state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Secondary battery 4 Positive terminal 5 Minus terminal 6 Temperature detection terminal 7 Outer case 9 Circuit board 10 Lead plate 11 Connection plate 12 Spacer 13 Sealing piece 25 Positive input / output terminal (protruding terminal) 31 Battery can 33 Power generation element

Continuation of the front page (51) Int.Cl. ⁷ identification code FI // H01M 10/40 H01M 10/40 Z (58) Investigation field (Int.Cl. ⁷ , DB name) H01M 2/34 H01M 2/02 -2/04 H01M 10/40-10/48 H02J 7/00-7/36

Claims (11)

(57) [Claims] 1. A battery can containing a power generating element in a bottomed cylindrical container, and a protruding terminal provided insulated from the battery can at a sealing portion for sealing an open end of the battery can. Or a secondary battery in which a negative electrode is respectively set, a secondary battery including a battery protection circuit integrally provided with a battery protection circuit for protecting the secondary battery from overcharge, overdischarge, and the like, A circuit board on which a battery protection circuit and a plurality of input / output terminals are formed is provided on the sealing portion, and the protruding terminal and the battery can are connected to the input / output terminals via a battery protection circuit, respectively, to thereby form a secondary battery. And a circuit board are integrated to form an intermediate completed product. This intermediate completed product is formed into a bottomed cylindrical shape by resin molding.
At the position corresponding to the input / output terminal on the bottom.
Insert into a rigid outer case with an opening
And the open end is closed with a sealing piece, and the intermediate finished product is
A secondary battery provided with a battery protection device, which is enclosed in a battery. 2. A battery can in which a power generating element is housed in a bottomed cylindrical container, and a protruding terminal provided insulated from the battery can in a sealing portion for sealing an open end of the battery can. Or a secondary battery in which a negative electrode is respectively set, a secondary battery including a battery protection circuit integrally provided with a battery protection circuit for protecting the secondary battery from overcharge, overdischarge, and the like, On the side of the sealing portion, a connection plate joined to the protruding terminal, a circuit board on which a battery protection circuit and a plurality of input / output terminals are formed, and a seating surface of the circuit board are formed to form a connection between the battery and the secondary battery. A spacer and a spacer are provided, and by connecting the lead plate and the connection plate joined to the battery can respectively to predetermined positions on the circuit board, the secondary battery and the circuit board are integrated, When the secondary battery and the battery protection circuit are electrically connected, Positive and negative electrodes are formed on the intermediate product that is connected to the input and output terminals via the battery protection circuit,
This intermediate product is formed into a bottomed cylinder by resin molding.
And inserted into a rigid outer case having an opening formed at a position corresponding to the input / output terminal on the bottom surface , closing the open end with a sealing piece, and sealing the intermediate product in the outer case. A secondary battery provided with a battery protection circuit. 3. An outer case for accommodating a secondary battery having an oblong cross-sectional shape has a substantially rectangular outer shape in cross-section, and an inner shape corresponding to the outer shape of the secondary battery. A secondary battery provided with the battery protection circuit according to claim 1 or 2, which is formed in a substantially oval shape. 4. The outer case is formed with a sealing piece having a long-side peripheral portion extending on the open end side of the bottomed square tubular shape, bending the sealing piece inward by hot pressing and forming the opposing portion. A secondary battery provided with the battery protection circuit according to any one of claims 1 to 3, wherein the intermediate completed product is sealed in an exterior case by melting and closing an open end. 5. A sealing strip are respectively uneven shape formed on the opposite long side of the rectangular open end, claim 1 any one unevenness is formed to fit fits together when folding A rechargeable battery comprising the battery protection circuit according to item 1. 6. A secondary battery provided with the battery protection circuit according to claim 2, wherein the sealing piece has a molten portion formed to be thick. 7. A secondary battery provided with the battery protection circuit according to claim 1, wherein the sealing piece is formed in such a size and shape that a gap is formed between the sealing pieces when the sealing piece is folded. 8. A secondary battery comprising the battery protection circuit according to claim 1, wherein a projection is provided on an inner surface of the sealing piece. 9. The exterior case is formed with a sealing piece having a side peripheral portion extending to the open end side of the bottomed rectangular tube shape, and after inserting an intermediate completed product, the sealing piece is inwardly pressed by a hot press. A secondary battery provided with the battery protection circuit according to any one of claims 1 to 3, wherein the secondary battery is melted to close the open end. 10. The battery protection circuit according to claim 9, wherein the height of the hot press is set at a fixed position to absorb variations in the height of the intermediate finished product by the molding height of the molten resin. Rechargeable battery. 11. A secondary battery comprising the battery protection circuit according to claim 1, wherein a plurality of input / output terminals are arranged asymmetrically.