JP2000149918A - Secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery with a protecting circuit without constituting a pack battery by installing the protecting circuit for preventing overdischarge and overcharge in a sealing plate. SOLUTION: A protecting circuit constituted by mounting an electronic circuit 11 on a circuit board 10 is built in a sealing plate 8 for sealing an opening end of a battery case 15 in which a power generating element is housed. The circuit bord 10 is attached to the outside end of the sealing plate 8, a positive terminal plate 16 serving as a positive terminal of a secondary battery 1 and an S pole terminal plate 14 controling the operation of the electronic circuit 11 by outside connection are installed on the outside surface of the circuit board 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a battery protection device in a battery constituting a secondary battery such as a lithium ion secondary battery, and has a function of protecting the battery itself from overcharge and overdischarge. The present invention relates to a secondary battery configured as follows.

[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 a PTC element that prevents excessive discharge current due to a short circuit, etc., and a safety valve that releases the internal pressure by shutting off the current-carrying circuit due to an abnormal rise in battery internal pressure due to overcharging. The secondary battery itself has these protection functions. It is well known as a function. In addition, a protection circuit is provided in a lithium ion secondary battery to prevent overcharging and overdischarging, etc., and this protection circuit is generally provided in the form of a pack battery together with the lithium ion secondary battery in a case of the pack battery. It is housed and integrated. A battery pack in which such a battery and a protection circuit are housed in a case and integrated is a battery power source for a portable device such as a mobile phone using a secondary battery such as a lithium ion secondary battery. It is well known that it is widely used as an apparatus, and as a prior application patent, Japanese Unexamined Patent Application Publication No. 7-272748.
JP-A-8-320297, JP-A-9-32064
The one disclosed in Japanese Patent Publication No. 3 and the like is known.

[0003] In addition to the above-described overcharge and overdischarge prevention, the protection circuit can have functions such as interruption of excessive current, battery temperature monitoring, and the like. A secondary battery provided with a protection circuit can be formed without forming a battery pack, and a highly versatile secondary battery can be provided. The ones considered to have been designed for the purpose of containing the protection circuit in the battery include:
Japanese Patent Application Laid-Open No. 8-31460 discloses a battery pack in which components such as a protection circuit are disposed above a battery, and the protection circuit and the battery are further housed in an outer case. It is nothing more than the form of a battery. What is required of a secondary battery provided with a protection circuit is that the protection circuit is housed in its battery case while having substantially the same dimensions and shape as a conventional secondary battery without a protection circuit.

The inventor of the present application has developed a secondary battery in which a protection circuit is housed in the battery in accordance with the above-mentioned gist, and disclosed in Japanese Patent Application Nos. Hei.
No. 8896. FIG. 18 shows an embodiment of the present invention, in which a battery protection device including the protection circuit 27 is provided in a sealing plate 50 for sealing an open end of a battery case containing a power generation element.

In FIG. 18, a circuit board 38 on which an electronic circuit 27 for forming a protection circuit is formed is provided in a sealing plate 50.
A battery protection device including a PTC element 21 that is a critical temperature resistor for preventing an excessive current such as a short circuit, and a current cutoff mechanism 49 that breaks due to an abnormal rise in the internal pressure of the battery and cuts off an energizing circuit and discharges an abnormal internal pressure. Are arranged. The positive electrode of the power generating element is connected to the circuit board 38 through the current cutoff mechanism 49 and the PTC element 21, and a positive electrode cap 39 serving as a positive electrode terminal of the battery and an S electrode for externally connecting the negative side of the electronic circuit 27 from the circuit board 38. The cap 37 is electrically connected.

FIG. 19 shows the above configuration as an electrical connection diagram. The electronic circuit 27 includes a battery protection IC 52 having functions such as overcharge control, overdischarge control, and overdischarge current detection. And an FET 53 for turning on / off the positive-side energizing circuit by a control signal. The negative electrode side of the electronic circuit 27 is the S pole cap 3
7, the battery is electrically connected between the S-pole cap 37 and the battery case 48 constituting the negative electrode terminal of the secondary battery when the secondary battery is set in a device or a charger using the secondary battery. When connected, it becomes operational,
When this secondary battery is not set in the device,
Although the power is very small, it is configured so that power consumption by the electronic circuit 27 does not occur. As shown, the power generation element 5
The positive-side current-carrying mechanism 4 described above includes
9, the PTC element 21 and the electronic circuit 27 are arranged in series, so that it is configured as a secondary battery having a triple battery protection function.

[0007]

However, in the construction of the above-mentioned secondary battery, when the S-pole cap 37, the circuit board 38, and the like are caulked and fixed at their peripheral portions by the sealing bottom plate 47, the sealing plate 50 is completed. , Circuit board 38
In addition, stress is applied to the electronic circuit 27, and when the sealing plate 50 is fixed by caulking to the battery case, the stress is similarly applied, and there is a problem that the protection circuit function is impaired. In addition, the protection circuit 27 approaches the current cutoff mechanism 49.
Is arranged, the deformation space of the current interrupting mechanism 49, which is deformed and ruptured due to an abnormal rise in the internal pressure of the battery, is limited, and the accuracy of the deformation rupture is difficult to obtain.

An object of the present invention is to eliminate a failure in assembling and processing a battery in a secondary battery in which a protection circuit is provided in the battery, and to provide a battery protection device functioning with high accuracy. Another object is to provide a battery.

[0009]

According to a first aspect of the present invention for achieving the above object, a power generating element is accommodated in a battery case formed in a bottomed cylindrical shape, and an opening end of the battery case is provided with a battery protection device. In a secondary battery that is sealed by a sealing plate containing therein, the battery protection device is overcharged on a circuit board,
An electronic circuit for protecting the battery from over-discharge or the like is formed, and this circuit board is provided as a protection circuit disposed on the battery outer end of the sealing plate such that the electrode terminals formed on one surface side are exposed to the outside. It is characterized by comprising.

According to this configuration, the protection circuit is provided in the sealing plate, and the electrode terminal through which the electronic circuit forming the protection circuit passes is mounted so as to be exposed to the outside.
A protection circuit is built in the secondary battery itself, and a secondary battery with a protection circuit is configured regardless of the configuration of a battery pack or the like.
The protection function provided by this protection circuit for preventing overcharge, overdischarge, excessive discharge current, and the like prevents battery damage due to equipment failure or abnormal use.

According to a second aspect of the present invention for achieving the above object, a power generating element is housed in a battery case formed in a cylindrical shape with a bottom, and an opening end of the battery case is provided with a sealed battery protection device. In a secondary battery sealed by a plate,
In the battery protection device, an electronic circuit for protecting the battery from overcharge, overdischarge, and the like is formed on a circuit board, and the circuit board is sealed by exposing electrode terminals formed on one side thereof to the outside. It is characterized by comprising a protection circuit provided at the outer end of the battery of the plate, and a current interrupting means for interrupting the energizing circuit and releasing the internal pressure when the battery internal pressure rises abnormally.

According to this configuration, since the protection circuit and the current cutoff means are provided in the sealing plate, the protection circuit is provided in the secondary battery itself, and the protection circuit is provided regardless of the configuration of the battery pack or the like. The current interrupting means cuts off the current-carrying circuit even when the protection circuit is broken, thereby preventing battery damage due to equipment failure or abnormal use.

According to a third aspect of the present invention for achieving the above-mentioned object, a power generating element is accommodated in a battery case formed in a bottomed cylindrical shape, and an opening end of the battery case has a battery protection device mounted therein. In a secondary battery sealed by a plate,
In the battery protection device, an electronic circuit for protecting the battery from overcharge, overdischarge, and the like is formed on a circuit board, and the circuit board is sealed by exposing electrode terminals formed on one side thereof to the outside. A protection circuit disposed at the outer end of the battery of the plate, excessive current blocking means for preventing conduction when excessive current is discharged due to a short circuit, etc., and current interrupting means for interrupting the conducting circuit and releasing the internal pressure when the internal pressure of the battery is abnormally increased. And characterized by comprising:

According to this configuration, the protection circuit is provided in the sealing plate.
Since the excessive current blocking means and the current blocking means are provided, the secondary battery itself has a triple battery protection function, and the secondary battery itself is equipped with a battery protection device regardless of the configuration of the battery pack or the like. be able to.

In each of the above structures, the circuit board constituting the protection circuit has a positive electrode terminal of the battery at the center on one side,
An external connection electrode terminal serving as a ground portion of the protection circuit is formed in the peripheral portion, and a positive electrode connection electrode connected to the positive electrode of the power generation element is formed in the peripheral portion on the other surface side of the circuit board. A predetermined position between the sides is connected by a through hole. One side of the circuit board is disposed so as to be exposed to the outside from the sealing plate, so the positive electrode terminal functions as the positive terminal of the secondary battery, and the external connection electrode terminal is connected to the battery case that forms the negative terminal Doing so activates the protection circuit.

The electrode terminals can be formed by attaching a metal plate to a conductor pattern of a circuit board by soldering or a conductive adhesive, and by connecting the metal plate, the secondary battery can be electrically connected to the device. It is suitable for a dynamic connection.

Further, by forming a projection at the center of the outer surface side of the metal plate to be joined to the positive electrode terminal, it is possible to improve the connectivity when making a contact connection with the device side connection terminal. Further, when the leads are connected by welding, the welding current can be improved by the concentration of the welding current of resistance welding to the projections.

The metal plate is formed of a nickel plate, a gold-plated metal plate, or a metal plate of the same material as the battery case. In the case of a plate, corrosion resistance is excellent, and contact resistance can be reduced by gold plating. Also, by using the same material as the battery case, the welding conditions for resistance welding when connecting the leads can be easily adjusted.

The circuit board is fixed to the sealing plate at the outer periphery and supported on a support member electrically connected to the positive electrode of the power generating element. By being configured to be joined by the conductive adhesive, the circuit board is attached to the sealing plate, and at the same time, the electrical connection to the protection circuit is made.

Further, by forming the projection for positioning the circuit board on the support member, not only the work of mounting the circuit board but also the positioning at the time of connection becomes easy.

Further, by coating the electronic circuit portion of the protection circuit with a resin, it is possible to improve the moisture resistance of the electronic circuit portion and the anticorrosion from the electrolyte component and the like.

Further, by caulking and fixing the sealing plate to the battery case, the circuit board is attached to a predetermined position of the sealing plate, so that the sealing plate is swaged at the time of assembling the sealing plate and the sealing plate is caulked to the battery case. It is possible to prevent the circuit board from being distorted or damaged during fixing.

The protection circuit is always energized by providing a current-carrying member for electrically connecting the battery case forming the negative electrode terminal of the battery and the external connection electrode terminal on the circuit board. This makes it possible to eliminate components such as a connecting member for connecting the external connection electrode terminal to the negative electrode terminal on the device side when the device is set in the device. Self-discharge loss during long-term storage due to constant energization of the protection circuit is not a problem because it is charged by using it in a device or a charger before it is used in a device as in the conventional battery configuration. No.

Further, the current-carrying member is formed in a bottomed cylindrical shape having an inside diameter fitted to the opening end side of the battery case by providing an opening at the center and the periphery of the bottom surface. By fitting into the end side, it is possible to electrically connect with the external connection electrode terminal on the circuit board, and a stable fitting state is obtained. The electrical connection can be further stabilized by joining the current-carrying member and the external connection electrode terminal with a solder joint or a conductive adhesive.

The current-carrying member is fitted from the opening end side of the battery case and is formed so as to press-fit into a groove formed on the circumference of the battery case, so that the fitting position is stably maintained. You.

Further, by forming the current-carrying member so that it can be welded to the battery case at the cylindrical portion, the electric connection and the fitted state can be stably performed.

The current-carrying member is made of a metal material having a spring property, a metal material having excellent weldability with the battery case, or the same metal material as the battery case. It is preferable to use a metal material excellent in weldability when welding the current-carrying member and the battery case by welding the current-carrying member and the battery case. Will be sure.

Further, since the surface of the current-carrying member is covered with the heat-shrinkable tube together with the battery case, it is possible to eliminate a sense of incongruity in appearance due to the provision of the current-carrying member.

Further, by arranging an insulating member between the current-carrying member and the metal plate joined to the positive electrode terminal,
The insulation between the positive and negative electrodes can be improved.

Further, the current-carrying member is formed by applying an insulating coat to a surface portion excluding a peripheral portion of a bottom surface thereof.
The peripheral portion of the bottom surface functions as a negative electrode terminal, and positive and negative input / output terminals are configured on the same direction surface of the battery together with the positive electrode terminal viewed from the central opening, thereby simplifying the battery connection structure of the device. The insulating coat functions as an insulating portion between these positive and negative terminals.

[0031] Further, since the opening end of the battery case in which the sealing plate is fixed by caulking is electrically connected to the connecting member joined to the external connection electrode terminal, the external member can be externally connected without using a conducting member. The connection electrode terminal can be connected to the battery case.

Further, a fixing member is fixed on the outer peripheral side together with the supporting member in the sealing plate, and a fixing member on the inner peripheral side facing the supporting member with the circuit board interposed therebetween is provided. To secure the circuit board by fastening the circuit board and the fixing member by the fastening means with the circuit board interposed therebetween, so that the peripheral portion of the circuit board is held from both sides, so that a strong fixing structure is obtained. Can be.

The above-mentioned fastening means can be formed by a resin rivet which is formed by melting and molding one end side of the circuit board and the fixing member through which the fixing member is penetrated. Fastening can be performed while ensuring electrical insulation.

The fastening means is formed of a metal member which penetrates the fixing member and the circuit board through an insulating material and is fixed to the supporting member, so that the circuit board is fixed to the battery case after the sealing plate is fixed to the battery case. Can be attached to the sealing plate, and the sealing plate can be easily caulked to the battery case.

Further, by forming an opening in a required component of the sealing plate toward the outside in a direction orthogonal to the cylinder direction of the battery case, when the gas pressure abnormally increased in the battery is discharged, Since the opening is formed in a direction orthogonal to the ejection direction, it is possible to prevent the risk that the battery will jump out due to gas discharge.

Further, the surface of the battery case is formed by insulatingly covering the central portion of the bottom surface, leaving an exposed surface corresponding to the positive electrode terminal and an exposed surface at a predetermined circumferential portion of the side peripheral surface.
The insulating coating on the bottom surface functions as an insulating layer with the counterpart battery at the time of series connection, and the exposed surface of the circumferential portion can obtain negative connection to the battery case on the side peripheral surface.

Further, by forming a concave portion having a diameter larger than the outer dimension of the positive electrode terminal at the center of the bottom surface of the battery case, the positive electrode terminal of the mating battery is positioned by fitting into the concave portion during serial connection.

Further, since the secondary battery can be formed to have substantially the same outer dimensions as a secondary battery in which a protection circuit is not provided, compatibility with a conventional battery can be obtained as a standard size.

[0039]

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 each of the embodiments described below, the configuration of the present invention is applied to a cylindrical lithium ion secondary battery. Each of the drawings showing the battery configuration is shown in the drawing, which is a characteristic configuration of the present invention. Is shown as a cross-sectional view in the diameter direction, and the configuration inside the battery case in which the power generation element is accommodated is omitted. It should be understood that the configuration of the power generating element is the same as that of a general lithium ion secondary battery.

Referring to FIG. 1, a secondary battery 1 according to a first embodiment of the present invention includes a battery case 15 formed in a cylindrical shape having a bottom and a power generation element (not shown) housed therein.
A sealing plate 8 is fixed to the open end side of the battery case 15 by caulking via an outer gasket 13 so that the open end of the battery case 15 is sealed.

The sealing plate 8 is composed of a sealing bottom plate 17, a lower metal thin plate 22 and an upper metal thin plate 23 constituting current interrupting means, a PTC element which is a ring-shaped critical temperature resistor (excessive current). (Blocking means) 21, a board supporting plate (supporting member) 18, and a circuit board 10 on which an electronic circuit 11 forming a protection circuit is formed.

The sealing plate 8 is a bottomed cylindrical battery case 1.
5 is formed in a disk shape for closing the opening end, and each component is also formed in a circular shape. FIG. 2 is a plan view (a) and a side view (b) of a substrate support plate 18, which is one of the components. The substrate support plate 18 is formed in a hat shape having an opening 18b in the center, and has a rising portion. Exhaust holes 18a at multiple locations
Are formed. A flat portion formed in a ring shape around the opening 18b supports the circuit board 10 and
It serves as an electrical connection to the circuit board 10.

The lower metal sheet 22, the upper metal sheet 23, P
The TC element 21 and the substrate support plate 18 are laminated at their peripheral portions, and the inner gasket 1 is formed by the peripheral portion of the sealing bottom plate 17.
9 is fixed by pinching. Further, the circuit board 1
Numeral 0 is placed on the substrate supporting plate 18 with the surface on which the electronic circuit 11 is formed facing the inside of the sealing plate 8 and joined to the substrate supporting plate 18 by a joining method described later. close. As described above, a battery protection device including a current interrupting unit, an excessive current preventing unit, and a protection circuit is configured in the sealing plate 8.

As shown in FIG. 3 (a), the circuit board 10 has an electronic circuit 11 at a central portion on the other side facing the inside of the sealing plate 8, and a peripheral portion at the peripheral portion. Board 1
A ring-shaped conductor pattern for positive electrode connection (positive electrode for connection) 29 is formed for electrical connection to 8. After the electronic components are mounted, the central portion of the electronic circuit 11 is coated with a resin by resin printing or resin molding, thereby improving the moisture resistance and corrosion resistance of the electric circuit portion.
In addition, one surface facing the outside of the sealing plate 8 is
As shown in (b), a positive electrode conductor pattern (positive electrode terminal) 30 is formed at the center and an S electrode conductor pattern (external connection terminal) 31 is formed at the periphery. Conductive patterns formed on one surface side and the other surface side of the circuit board 10 are conductively connected at predetermined positions by through holes 32, and are configured as an electric circuit in which the one surface side and the other surface side are integrated. .

When the circuit board 10 is mounted on the substrate support plate 18, the positive electrode bonding conductor pattern 29 comes into contact with the ring-shaped flat portion of the substrate support plate 18. The circuit board 10 is fixed on the board supporting plate 18, and the positive electrode connecting conductor pattern 29 of the circuit board 10 and the board supporting plate 1 are joined together.
8 are electrically connected.

As shown in FIG. 4, the circuit board 10 is formed as a circuit board 10a in which a circular opposing position is cut off by a straight line, so that the circuit board 10a mounted on the board support plate 18 is connected to the positive electrode. Soldering between the conductor pattern 29 and the substrate support plate 18 or joining with a conductive adhesive can be facilitated. Also, the circuit board 10,
The electronic circuit 11 formed on the circuit board 10a can be formed not only on the other surface side of the circuit board 10, 10a but also on one surface side according to the state of the circuit configuration.

The circuit boards 10, 10a are connected to the board supporting plate 1
8, as shown in FIG.
By forming the cut-and-raised portions (protruding portions) 34 at a plurality of predetermined positions surrounding the periphery of 8, the positioning at the time of attaching the circuit board 10 to the board support plate 18 becomes easy,
Workability at the time of assembling the sealing plate 8 can be improved.

As shown in FIG. 1, a positive electrode terminal plate (metal plate) 16 formed in a disk shape is joined to the positive electrode conductor pattern 30 by soldering or a conductive adhesive. Further, as shown in FIG. 1, the S-pole conductor pattern 31 also has a ring-shaped S-pole terminal plate (metal plate).
14 are joined by soldering or a conductive adhesive. The positive electrode terminal plate 16 and the S-electrode terminal plate 14 are formed of a metal material having a small contact resistance with a contact terminal on the device side and excellent in corrosion resistance, and may be a pure nickel material, a gold-plated metal material, or the like. In addition, since the positive electrode terminal plate 16 is formed of the same material as the battery case 15, the welding conditions for resistance welding are easily adjusted, which is preferable. Furthermore, by providing a projection at the center of the positive electrode terminal plate 16,
The contact property with the contact terminal on the device side is improved, and when resistance welding is performed on the connection lead, the weld current can be improved by concentration of the welding current on the protruding portion.

The positive terminal plate 16 and the S terminal plate 14
Is useful as a contact portion or a joint portion when electrically connecting the secondary battery 1 to a device. However, the conductor pattern itself of the circuit board 10 can be used as a contact portion or a joint portion. If the circuit boards 10 and 10a are formed thick, direct connection to a conductor pattern is possible without joining metal plates.

With the above configuration, the power supply circuit of the secondary battery 1 is configured as follows. The negative electrode of the power generation element accommodated in the battery case 15 is connected to the battery case 15, and the battery case 15 forms a negative electrode terminal of the secondary battery 1. On the other hand, the positive electrode lead pulled out from the positive electrode of the power generation element is connected to the sealing bottom plate 17, and the positive electrode side energizing circuit includes a sealing bottom plate 17, a lower metal thin plate 22, a welding point A between the lower metal thin plate 22 and the upper metal thin plate 23, Upper metal sheet 23, PTC element 21, substrate support plate 1
8, the positive electrode bonding conductor pattern 29 of the circuit board 10, the electronic circuit 11, the positive electrode conductor pattern 30 of the circuit board 10, and the positive terminal plate 16 are formed as a circuit connected in this order.

FIG. 7A is an electric connection diagram showing an energization circuit of the secondary battery 1. The negative electrode of the power generation element 51 housed in the battery case 15 is connected to the battery case 15. Is the negative terminal. On the other hand, the positive electrode of the power generating element 51 is connected to the electronic circuit 11 through the current interrupting means 24 composed of the lower metal sheet 22 and the upper metal sheet 23 and the PTC element 21, and is turned on / off by the battery protection IC 25.
It is connected to the positive terminal plate 16 through the FET 26 that is FF controlled. The negative side of the power supply circuit of the electronic circuit 11 is connected to the S-pole terminal plate 14. As described above, the secondary battery 1 has a three-terminal structure in which the input / output terminals are constituted by the positive electrode terminal plate 16 (+), the S-electrode terminal plate (S), and the battery case (-).

When the secondary battery 1 having this configuration is set in a battery-using device, and the S-pole terminal plate 14 and the negative electrode terminal, that is, the battery case 15 are short-circuited on the device side, the electronic circuit 1
1, the secondary battery 1 can be used in a state where the secondary battery 1 is protected from overcharge, overdischarge, excessive discharge current, and the like at the same time as the input and output of the positive electrode through the electronic circuit 11 are performed. By configuring the electronic circuit 11 to operate in a state where the secondary battery 1 is set in the device in this way, even when the secondary battery 1 is not used, that is, when the secondary battery 1 is stored for a long time without being set in the device, The power consumption of the electronic circuit 11 does not occur, and self-discharge loss due to long-term storage is prevented even with a small power consumption of the electronic circuit 11.

Incidentally, the battery is not always expected to be used in a normal state, and must be configured so as to cope with a failure of the device or an abnormal use state.
In particular, in a battery having a high energy density such as a lithium ion secondary battery, it is important to deal with an abnormal state. The battery protection device configured in the sealing plate 8 acts on an abnormal state as follows.

The lower metal thin plate 22 and the upper metal thin plate 23 constitute a current interrupting means, and also have a function as a discharge valve for a gas generated abnormally in the battery. When the internal pressure of the battery abnormally rises due to the generated gas, the internal pressure of the battery extends from the opening 17a formed in the sealing bottom plate 17 to the lower metal thin plate 22, and deforms the lower metal thin plate 22 to the outside of the battery. Since the center of the lower metal sheet 22 is welded at the welding point A to the center of the upper metal sheet 23 bulging the center of the upper metal sheet 23 toward the inside of the battery, the deformation of the lower metal sheet 22 to the outside of the battery does not occur. Pressure is applied in a direction to reverse the bulging portion of the upper thin metal plate 23. When the deformation proceeds, the lower metal thin plate 22 formed on the flat surface breaks from the easily breakable portion 22a formed in a C-shape and cuts off the energizing circuit. When the lower metal sheet 22 breaks, the internal pressure reaches the upper metal sheet 23 to reverse the bulging portion, and further pressurization causes the easily breakable section 23 similarly formed in the upper metal sheet 23 to have a C-shaped thin wall.
a breaks. When the lower metal thin plate 22 and the upper metal thin plate 23 are broken, there is no barrier between the inside of the battery and the inside of the sealing plate 8, so that the gas is discharged to the outside through the exhaust holes 18 a formed in the substrate support plate 18. . Since the exhaust hole 18a is provided on the side surface of the battery, the exhaust hole 18a intersects with the direction in which the flammable gas is discharged from the inside of the battery.

In the case where the positive electrode and the negative electrode of the secondary battery 1 are short-circuited, the temperature of the PTC element 21 sharply rises due to an excessive current caused by the short-circuit, and when the PTC element 21 reaches a predetermined critical temperature, the resistance value of the PTC element 21 increases. A sudden rise prevents excessive current discharge to prevent battery damage.

The electronic circuit 11 having the protection circuit formed thereon
Has the function of detecting the overcharge state or the overdischarge state and shutting off the positive electrode energizing circuit, the function of shutting off the positive electrode energizing circuit when an excessive discharge current flows, and the function of detecting the battery temperature and exceeding the predetermined temperature. Since a function of shutting off the positive electrode circuit can be arbitrarily included in the circuit configuration, a secondary battery having a high energy density and limited charging conditions and temperature conditions can be effectively used.

Next, a secondary battery 2 according to a second embodiment of the present invention will be described. Note that the same reference numerals are given to components common to the configuration of the first embodiment, and description thereof will be omitted.

In FIG. 6, the secondary battery 2 according to the second embodiment has basically the same configuration as the secondary battery 1 according to the first embodiment, but has the same structure as the secondary battery 1 formed on the circuit board 10. The polar conductor pattern 31 is configured to be electrically connected to the battery case 15 by a current-carrying cap (current-carrying member) 20. That is, the S pole terminal and the negative electrode terminal are connected in advance, and the protection circuit 11 is in a state of being always energized. When this is shown as an electrical connection diagram, it is as shown in FIG. 7B. Since the S-pole conductor pattern 31 is connected to the battery case 15 which is a negative electrode terminal on the battery side by the energizing cap 20, the secondary battery 2 Has a two-pole terminal configuration. In this configuration, since power is always supplied from the power generation element 51 to the protection circuit 11, self-discharge loss occurs when the protection circuit 11 is stored for a long time without being set in the device. However, since the connection configuration on the device side for the battery set is simplified, the device is suitable for many devices using a battery power supply sold with the secondary battery 2 set.

As shown in FIG. 8, the energization cap 20 is formed in a bottomed cylindrical shape having an inside diameter fitted to the open end side of the battery case 15, and exposes the positive electrode terminal plate 16 to the outside at the center of the bottom surface. 20d, and a plurality of discharge holes 20a for discharging gas. After the sealing plate 9 is fixed to the open end of the battery case 15 by caulking, the energizing cap 20 is fitted onto the battery case 15 from the sealing plate 9 side as shown in FIG. A fitting portion 20b is fitted into a circumferential groove 15a formed in a circumferential direction for fixing the plate 9, and is fixed in position, and is electrically connected to the battery case 15. Further, at the position where the bottom surface of the energizing cap 20 is in contact with the S-pole conductor pattern 31 on the circuit board 10, the space between them is joined by soldering or a conductive adhesive. In order to facilitate the heating of the joining portion when performing this solder joining, FIG.
As shown by a broken line in (a), it is preferable to form notches 20f at a plurality of positions of the opening 20d.

8 (b) and 8 (c), a cut 20c can be formed in the direction of the cylindrical axis of the current-carrying cap 20 in order to ensure the fitting into the battery case 15 and the pressure contact. In order to reliably perform such electrical connection by pressure contact, a metal material having a spring property, such as phosphor bronze, is preferable as the material of the energization cap 20. Also,
As shown in FIG. 8C, in order to make the electrical connection more reliable, the lower part of the fitting part 20b of the energizing cap 20 is formed to be extended, and the extension part 20e is welded to the battery case 15. can do. In order to perform welding reliably, it is desirable that the material of the current-carrying cap 20 matches the material of the battery case 15, and in the case of a lithium ion secondary battery, a nickel-plated steel plate is usually used.
It is preferable that 0 is also formed of a nickel-plated steel plate.

Further, as shown by the broken line in FIG. 6, by disposing the ring-shaped insulating member 33 on the current-carrying cap 20, the insulation between the positive and negative electrodes is enhanced.
Although not shown, an opening is formed in the insulating member 33 at a portion corresponding to the discharge hole 20a formed in the energization cap 20 so that the discharge hole 20a is not closed. . Also, instead of this insulating member 33, an insulating coating 54 is applied to a portion shown by oblique lines in FIG. 8A, and the periphery of the bottom surface of the current-carrying cap 20 is configured as a negative input / output terminal of the secondary battery 2. As shown in FIG. 6, the secondary battery 2 has a positive input / output terminal (a positive electrode terminal plate 1) on the same surface.
6) and a negative input / output terminal are provided,
The battery connection structure on the device side can be simplified. In this input / output terminal structure, since the plus / minus input / output terminals are located at both ends of the battery in the conventional battery, the discrimination from the secondary battery 2 having this configuration is remarkable, and the compatibility with the conventional battery is obtained. Therefore, it is possible to prevent the occurrence of failure due to the conventional battery and the secondary battery 2 having this configuration being erroneously set in the device. This structure that eliminates compatibility with conventional batteries is an important requirement, especially when the batteries have different nominal voltages.

When the surface of the battery case 15 is covered with the heat-shrinkable tube, the current-carrying cap 20 can be more securely fixed to the battery case 15 by mainly covering the current-carrying cap 20.

Next, a secondary battery 3 according to a third embodiment of the present invention will be described with reference to FIG. Note that the same reference numerals are given to components common to the configurations of the first and second embodiments, and description thereof will be omitted.

Referring to FIG. 9, a secondary battery 3 has a structure in which an S-pole conductor pattern 31 and a battery case 15 are electrically connected to each other by using an energizing cap 20 in the secondary battery 2 according to the second embodiment. Instead of the connection plate (connection member) 41
The battery case 15 is brought into contact with the S-pole conductor pattern 31 to electrically connect the battery case 15 to the S-pole conductor pattern 31.

The sealing plate 12 used for the secondary battery 3 includes a connecting plate 41 joined to the S-pole conductor pattern 31 of the circuit board 10 at an inner peripheral portion thereof. When the sealing plate 12 is caulked and fixed by the battery case 15, it is clamped and fixed by the battery case 15 via the outer gasket 35.

When the sealing plate 12 is fixed, the open end of the battery case 15 bent inward is connected to the connection plate 4.
1 and is electrically connected to the battery case 15 through the connection plate 41 of the S-pole conductor pattern 31. In order to perform more reliable electrical connection, the battery case 15 and the connection plate 41 can be connected by laser welding or resistance welding.

Next, a fourth embodiment of the present invention will be described.
This will be described with reference to FIGS.

Elements common to those in the first, second, and third embodiments are denoted by the same reference numerals, and description thereof is omitted. Further, each drawing shows the sealing plates 44, 45, 46 before being attached to the battery case 15 as 断面 cross sections in the diameter direction. The sealing plate 4 according to the fourth embodiment.
The configurations of 4, 45, and 46 are characterized by the mounting structure of the circuit board 7.

In FIG. 10, the periphery of the circuit board 7 is
The inner support plate (support member) 55 faces the other surface, and the inner peripheral flat surface of the outer support plate (fixing member) 58 faces one surface side. The inner support plate 55, the circuit board 7, and the outer support plate 58 respectively. The resin rivet 62 is inserted into the opening hole formed in the substrate supporting plate 5.
5 through the outer support plate 58 side is melt-molded with an impulse welder.
Between the parties. Such fastening portions are performed at a plurality of locations around the circuit board 7, and the circuit board 7 is attached to the inner support plate 55.
And the outer support plate 58. As shown in the drawing, the surface of the outer support plate 58 facing the substrate support plate 55 is coated with an insulating coating 61 having excellent abrasion and insulation properties, for example, by a dent process, so as to electrically connect with the inner support plate 55. Keeps insulation. These inner support plate 55 and outer support plate 58
As shown in the figure, the sealing bottom plate 17 is folded and pressed together with the PTC element 21, the upper metal thin plate 23, and the lower metal thin plate 22 via the inner gasket 19 as shown in the drawing. The sealing plate 44 thus formed is swaged and fixed to the open end of the battery case 15 via the outer gasket 13.

In this configuration, the power supply circuit from the positive electrode of the power generating element to the positive electrode side is connected to the other side of the circuit board 7 via the sealing bottom plate 17, the lower metal thin plate 22, the upper metal thin plate 23, the PTC element 21, and the inner support plate 55. It is connected to the positive electrode connecting conductor pattern 29 formed in the peripheral portion. Since the outer support plate 58 is insulated from the inner support plate 55 and is connected to the S-pole conductor pattern 31 formed on the peripheral portion on one surface side of the circuit board 7 by the fastening structure,
This is used as an S pole terminal as in the configuration of the first embodiment.
The battery may be configured as a terminal type battery, or may be configured as a two-terminal type battery which is connected to the battery case 15 which is the negative terminal of the battery and is always energized to the protection circuit.

FIG. 11 shows a structure in which the circuit board 7 is fastened and fixed by screws. Metal screws (metal members) 63 are electrically connected to the outer support plate 59 and the circuit board 7 by an insulating washer 64 from the outer support plate 59 side. The outer support plate 5 is inserted in a state of being electrically insulated, and is screwed into the inner support plate 56.
The peripheral portion of the circuit board 7 is fastened and fixed by the inner support plate 9 and the inner support plate 56. The other configuration is the same as the fastening structure using the resin rivet 62, and is formed as the sealing plate 45. The head of the metal screw 63 can be insulated and coated, for example, by a dent process.

FIG. 12 shows a modified example of the fastening structure using the resin rivet 62 and the fastening structure using the metal screw 63. As shown in the drawing, the inner support plate 57 has an S-shaped cross section. Is formed. With the configuration of the inner support plate 57, deformation due to stress when the outer support plate 58 and the inner support plate 57 are fixed by caulking by the sealing bottom plate 17 is prevented, and distortion applied to the circuit board 7 is reduced.

In each configuration according to the fourth embodiment, the inner support plates 55, 56, 57 and the outer support plates 58, 59
Opening 55
a, 56a, 57a, 58a, and 59a are formed, and these constitute an exhaust port at the time of gas release at an abnormal internal pressure. Further, the positive electrode terminal plate 6 joined to the positive electrode conductor pattern 30 formed in the central portion on one surface side of the circuit board 7 is formed of a material having a thickness higher than the height of the resin rivet 62 or the metal screw 63.

As in the configuration of each embodiment described above,
When a protection circuit is provided in the battery, the function of preventing excessive current discharge can be provided by the configuration of the electronic circuit 11. Therefore, the provision of the PTC element 21 having a function of preventing excessive current discharge due to a short circuit or the like is eliminated. You can also. That is, if a function of detecting an excessive current is provided as a function of the electronic circuit 11, the conduction circuit can be cut off when an excessive current is detected, so that the PTC element 21 can be eliminated. Further, since the protection circuit has a function of preventing overcharging, it is possible to prevent an abnormal increase in the internal pressure of the battery due to decomposition of the electrolytic solution due to the overcharging, and to eliminate the internal pressure of the battery along with the elimination of the PTC element. It is also possible to abolish the current interrupting means for interrupting the energizing circuit due to abnormal rise of the current. This P
The structure in which the TC element 21 is eliminated and the structure in which the PTC element 21 and the current cutoff means are eliminated will be described below.

FIG. 13 shows the structure of a secondary battery 4 according to the fifth embodiment.
The C element 21 is omitted. By providing the electronic circuit 11 with a function of preventing excessive current discharge, the arrangement of the PTC element 21 can be eliminated, and the electronic circuit 11 is configured as a sealing plate 40 having a simple structure.

The sealing plate 40 having this structure is provided in the order of the sealing bottom plate 17, the lower metal thin plate 22, the upper metal thin plate 23, the substrate supporting plate 18, and the circuit board 10 from the inside of the battery. The thin metal plate 23 and the substrate support plate 18 are caulked and fixed at the peripheral portion thereof by the sealing bottom plate 17 via the inner gasket 19. The sealing bottom plate 17 is lead-connected to a positive electrode of a power generation element (not shown), and includes a sealing bottom plate 17, a lower metal thin plate 22, a welding point A between the lower metal thin plate 22 and the upper metal thin plate 23, an upper metal thin plate 23, and a substrate support plate 18. From the circuit board 10
The positive electrode conduction path leading to the positive electrode connecting conductor pattern 29 is formed. The connection and operation on the circuit board 10 are the same as in the configuration of the first embodiment described above, and a description thereof will be omitted. Incidentally, also in this configuration, a two-terminal structure without the S-pole terminal plate 14 by providing the energizing cap 20 can be employed.

FIG. 14 shows a configuration of a secondary battery 5 according to the sixth embodiment. The sealing plate 65 is provided with only a protection circuit as a battery protection device. The sealing plate 65 includes a sealing bottom plate 66 and a shielding plate 6 from the inside of the battery.
7, the board supporting plate 18 and the circuit board 10 are arranged in this order.
9 is secured by caulking by the sealing bottom plate 66. The shielding plate 67 shields between the inside of the battery and the inside of the sealing plate 65, and the sealing inside the battery is maintained by the shielding plate 67. Further, the shielding plate 67 is welded to the central protruding portion of the sealing bottom plate 66 at a center position where the center portion is bulged toward the inside of the battery. Plate 67, substrate support plate 18
A positive current path is formed through the substrate support plate 18, the positive electrode connecting conductor pattern 29 of the circuit board 10 and the electronic circuit 11 constitute a positive electrode circuit having the positive terminal plate 16 as a positive input / output terminal. The shielding plate 67 has C
When the internal pressure of the battery rises abnormally due to abnormal use or the like, the swelling portion is inverted due to the abnormal internal pressure applied through the opening 66a formed in the sealing bottom plate 66 because the easily breakable portion 67a having a thin wall shape is formed. When it is pressurized in the direction of breaking, it breaks from the easily breakable portion 67a to cut off the positive electrode conduction circuit and discharges abnormal internal pressure to the outside through the exhaust hole 18a formed on the side of the substrate support plate 18. Circuit board 10
The above connection and operation are the same as in the configuration of the above-described first embodiment, and a description thereof will be omitted. Incidentally, also in this configuration, the power supply cap 20 is provided to
It can also be configured in a terminal structure.

The configuration of each of the embodiments described above is formed to have substantially the same outer dimensions as those of a conventional lithium ion secondary battery without a protection circuit. FIG. 15 shows the secondary battery 1 shown in the first embodiment and a secondary battery P without a conventional protection circuit symmetrically with respect to the center line. , Diameter and upper and lower dimensions are substantially the same. Therefore, the form formed as a battery pack for forming a protection circuit in the battery accommodating space of a device using a battery power supply becomes unnecessary, and the space for accommodating the battery power can be reduced, contributing to downsizing and weight reduction of the device. You can do it. The batteries can be connected in series and used, and each battery is provided with a protection circuit, and can be easily charged by the charging function of the device.

In consideration of the case where batteries are connected in series, a concave portion 68 can be formed at the center of the bottom surface of the battery case 15 as shown in FIG. Battery case 1
The insulating coating 69 applied to the surface of the fifth surface 5 can be formed leaving a part of the side peripheral surface and the concave portion 68 as shown in the drawing. A part of the side peripheral surface that is not covered is used as a negative terminal 70 for battery connection. This battery is a second
17 shows an example in which the present invention is applied to the secondary battery 2 shown in the embodiment, and can be used in series connection as shown in FIG. As shown in the figure, the positive electrode terminal plate 16 of the second rechargeable battery 2b connected in series comes into contact with the concave portion 68 of the first rechargeable battery 2a to make a series connection. Is pulled out from the minus terminal 70 of the second secondary battery 2b. FIG. 17 shows the case of two-series connection, but the same configuration can be applied to the case of two or more-series connection.

[0081]

As described above, according to the present invention, the protection circuit for protecting the battery from overcharging or overdischarging can be provided in the secondary battery with a simple structure, so that the assembling operation is not much different from the conventional structure. A secondary battery having a protection circuit can be manufactured. In addition, since the secondary battery can be formed in the same size as a conventional secondary battery without a protection circuit, the form in which the protection circuit is conventionally provided as a pack battery is unnecessary, and the battery of a device using the secondary battery as a power source is unnecessary. The storage space is reduced, and a highly versatile secondary battery is configured without using a specially shaped battery pack.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a secondary battery according to a first embodiment.

2A is a plan view showing a configuration of a substrate support plate, FIG.
(B) is a side view.

FIGS. 3A and 3B show the configuration of a circuit board; FIG.
Is a plan view of one side.

4A shows a modification of the circuit board, FIG.
(B) is a plan view of one surface side.

FIG. 5 is a sectional view showing a modification of the upper sealing plate supporting the circuit board.

FIG. 6 is a sectional view showing a configuration of a secondary battery according to a second embodiment.

FIG. 7A is a secondary battery according to the first embodiment,
(B) is a circuit diagram showing the configuration of the secondary battery according to the second embodiment by an electric circuit.

8A is a plan view showing a configuration of an energization cap, FIG.
(B) is a side view, (c) is a side view of a modification.

FIG. 9 shows a configuration of a secondary battery according to a third embodiment.
/ 2 sectional view.

FIG. 10 is a half sectional view showing the configuration of a sealing plate of a secondary battery according to a fourth embodiment.

FIG. 11 is a half sectional view showing the structure of a sealing plate of a secondary battery according to a fourth embodiment.

FIG. 12 is a half sectional view showing the configuration of a sealing plate of a secondary battery according to a fourth embodiment.

FIG. 13 is a sectional view showing a configuration of a secondary battery according to a fifth embodiment.

FIG. 14 is a sectional view showing a configuration of a secondary battery according to a sixth embodiment.

FIG. 15 is a cross-sectional view comparing a configuration of the present invention with a conventional configuration.

FIG. 16 is a perspective view showing a bottom structure and an insulating coating structure of a battery case.

FIG. 17 is a schematic view showing an example of series connection.

FIG. 18 is a cross-sectional view illustrating a configuration of a sealing plate of a secondary battery according to a conventional example.

FIG. 19 is a circuit diagram showing an electric circuit configuration of a secondary battery according to a conventional example.

[Explanation of symbols]

 1, 2, 3, 4, 5 secondary battery 8, 9, 12, 40, 44, 45, 46, 65 sealing plate 7, 10, 10a circuit board 11 electronic circuit 14 S pole terminal plate (metal plate) 15 battery Case 16 Positive electrode terminal plate (metal plate) 18, 42 Substrate support plate (support member) 20 Current carrying cap (current carrying member) 21 PTC element (excessive current blocking means) 22 Lower metal sheet (current interrupting means) 23 Upper metal sheet ( Current interrupting means) 29 Positive electrode connection conductor pattern (positive electrode connection electrode) 30 Positive electrode conductor pattern (positive electrode terminal) 31 S pole conductor pattern (external connection terminal) 32 Through hole 33 Insulating member 34 Cut-and-raised portion (projecting portion) 41) Connection plate (connection member) 55, 56, 57 Inner support plate (support member) 58, 59 Outer support plate (fixing member) 61 Insulation coating 62 Resin rivet 63 Metal screw (gold) Member) 64 insulating washer 68 recess 69 dielectric coating

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01R 12/32 H01R 9/09 ABG (72) Inventor Kazuto Masumoto 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Katsuhiko Mori, Inventor 1006 Kadoma, Kadoma, Osaka Pref. DD21 DD23 5H012 AA01 BB02 DD01 DD05 EE04 FF01 GG01 JJ01 5H022 AA09 AA18 BB03 CC02 CC08 CC12 CC13 CC30 KK01 5H029 AJ12 AL12 BJ27 CJ03 CJ05 DJ03 DJ05 EJ01 HJ12

Claims (27)

[Claims] 1. A secondary battery in which a power generation element is accommodated in a battery case formed in a bottomed cylindrical shape, and an open end of the battery case is sealed by a sealing plate having a battery protection device installed therein. An electronic circuit for protecting the battery from overcharge, overdischarge, etc. is formed on a circuit board, and the battery of the sealing plate is formed by exposing the circuit board to an electrode terminal formed on one side thereof. A secondary battery comprising a protection circuit provided at an outer end. 2. A secondary battery in which a power generation element is accommodated in a battery case formed in a bottomed cylindrical shape, and an opening end of the battery case is sealed by a sealing plate having a battery protection device therein. An electronic circuit for protecting the battery from overcharge, overdischarge, etc. is formed on a circuit board, and the battery of the sealing plate is formed by exposing the circuit board to an electrode terminal formed on one side thereof. A secondary battery comprising: a protection circuit provided at an outer end; and a current interrupting unit that interrupts an energizing circuit and releases internal pressure when the battery internal pressure abnormally rises. 3. A secondary battery in which a power generation element is accommodated in a battery case formed in a bottomed cylindrical shape, and an opening end side of the battery case is sealed by a sealing plate having a battery protection device therein. An electronic circuit for protecting the battery from overcharge, overdischarge, etc. is formed on a circuit board, and the battery of the sealing plate is formed by exposing the circuit board to an electrode terminal formed on one side thereof. A protection circuit provided at the outer end; an excessive current blocking means for preventing current flow when an excessive current is discharged such as a short circuit; and a current cutoff means for interrupting the current supply circuit and releasing the internal pressure when the battery internal pressure is abnormally increased. A secondary battery comprising: 4. A positive electrode terminal of a battery is formed in a central portion on one surface side of a circuit board, and an external connection electrode terminal serving as a grounding portion of a protection circuit is formed in a peripheral portion, and power is generated in a peripheral portion on the other surface side of the circuit board. The secondary battery according to any one of claims 1 to 3, wherein a positive electrode connection electrode connected to the positive electrode of the element is formed, and a predetermined position between one surface and the other surface is connected by a through hole. . 5. The secondary battery according to claim 1, wherein the electrode terminal is formed by attaching a metal plate to a conductor pattern of a circuit board by solder bonding or a conductive adhesive. 6. The secondary battery according to claim 5, wherein a projection is formed at a central portion on the outer surface side of the metal plate joined to the positive electrode terminal. 7. The secondary battery according to claim 5, wherein the metal plate is formed of a nickel plate, a gold-plated metal plate, or a metal plate of the same material as the battery case. 8. The circuit board is fixed to a sealing plate at an outer peripheral portion, and is supported on a supporting member electrically connected to a positive electrode of the power generating element. Claim 1 which is joined by a conductive adhesive.
4. The secondary battery according to claim 1. 9. The secondary battery according to claim 8, wherein a projection for positioning the circuit board is formed on the support member. 10. The secondary battery according to claim 1, wherein an electronic circuit portion of the protection circuit is coated with a resin. 11. The secondary battery according to claim 1, wherein the circuit board is attached to a predetermined position of the sealing plate after the sealing plate is fixed by caulking to the battery case. 12. The battery according to claim 1, further comprising a current-carrying member for electrically connecting a battery case constituting a negative electrode terminal of the battery and an external connection electrode on a circuit board. The secondary battery according to any one of the preceding claims. 13. The battery according to claim 12, wherein the current-carrying member is formed in a bottomed cylindrical shape having an inner diameter and having an opening at a center portion and a peripheral portion of the bottom surface and fitted to the opening end side of the battery case. Next battery. 14. The secondary according to claim 12, wherein the current-carrying member is fitted from the opening end side of the battery case and press-fitted into a groove formed on the circumference of the battery case. battery. 15. The secondary battery according to claim 12, wherein the current-carrying member is configured to be welded to the battery case at the cylindrical portion. 16. The current-carrying member according to claim 12, wherein the current-carrying member is formed of a metal material having a spring property, a metal material excellent in weldability with the battery case, or the same metal material as the battery case. Rechargeable battery. 17. An insulating member is provided between a current-carrying member and a metal plate joined to a positive electrode terminal.
The secondary battery according to claim 1. 18. The conductive member is formed by applying an insulating coating to a surface portion excluding a peripheral portion of a bottom surface thereof.
The secondary battery according to any one of claims 17 to 17. 19. The secondary battery according to claim 12, wherein the surface of the side peripheral surface of the current-carrying member is covered with a heat-shrinkable tube together with the battery case. 20. The battery according to claim 1, wherein an opening end of the battery case in which the sealing plate is fixed by caulking is electrically connected to the connection member joined to the external connection electrode terminal.
The secondary battery according to claim 1. 21. A fixing member having an outer peripheral side fixed in the sealing plate together with the supporting member, and a fixing member facing the supporting member on the inner peripheral side with the circuit board interposed therebetween, the supporting member being provided at a plurality of positions on the peripheral portion of the circuit board. The secondary battery according to any one of claims 1 to 3, wherein the secondary battery is configured to support the circuit board by fastening the circuit board and the fixing member by fastening means with the circuit board interposed therebetween. 22. The secondary battery according to claim 21, wherein the fastening means is formed by a resin rivet formed by melting and molding one end of the supporting member, the circuit board, and the fixing member. 23. The secondary battery according to claim 21, wherein the fastening means is formed of a metal member that passes through the fixing member and the circuit board via an insulator and is fixed to the supporting member. 24. The secondary according to claim 1, wherein a required component of the sealing plate is formed with an opening that opens outward in a direction intersecting with the cylinder direction of the battery case. battery. 25. The battery case according to claim 1, wherein the surface of the battery case is insulated so as to leave an exposed surface corresponding to the positive electrode terminal in the center of the bottom surface and an exposed surface at a predetermined circumferential portion of the side peripheral surface. The secondary battery according to claim 1. 26. The secondary battery according to claim 1, wherein a concave portion having a diameter larger than an outer dimension of the positive electrode terminal is formed in a central portion of a bottom surface of the battery case. 27. The secondary battery according to claim 1, wherein an external dimension of the secondary battery is substantially the same as that of a secondary battery having no protection circuit.