JP3154280B2 - Rechargeable battery - Google Patents

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 A secondary battery having a high energy density, such as a lithium ion secondary battery, is used for a short circuit in a battery peripheral circuit of a device using the secondary battery, a short circuit between positive and negative electrodes, overcharging and overdischarging. In order to prevent damage to the battery due to abnormal use, it is used with various protection functions. FIG.
Is a cross-sectional view of a sealed portion of a lithium ion secondary battery, which is configured by sealing an open end of a bottomed cylindrical battery case 61 containing a power generating element with a sealing portion 62. The sealing portion 62 includes a sealing bottom plate 64, a lower metal thin plate 65, an upper metal thin plate 66, and a PTC element 6 from the inside of the battery.
7. A sealing upper plate 68 is provided, which is clamped and fixed by a sealing bottom plate 64 via an inner gasket 69 at the peripheral portion, and the sealing portion 62 is caulked to the opening end of the battery case 61 via an outer gasket 63. By fixing, the open end of the battery case 61 is sealed.

In the above configuration, the positive and negative plates of the positive and negative electrodes constituting the power generating element are lead-connected to the sealing bottom plate 64, and the junction A between the sealing bottom plate 64, the lower metal thin plate 65, and the lower metal thin plate 65 and the upper metal thin plate 66. , Upper metal sheet 66, PTC element 6
7. An energization circuit communicating with the upper sealing plate 68 is formed, and the upper sealing plate 68 functions as a positive electrode input / output terminal of the secondary battery, and the battery case 61 to which the negative electrode plate is connected functions as a negative input / output terminal of the secondary battery. Function. In general, the input / output terminal of the positive electrode is allocated to the sealing upper plate 68 and the input / output terminal of the negative electrode is allocated to the battery case 61, but the reverse is also possible.

The lower metal sheet 65 and the upper metal sheet 66 are welded to each other at a joint point A at the center thereof, and deformed by the pressure applied through the opening of the sealing bottom plate 64 when the internal pressure of the battery rises abnormally. When the joining point A peels off, a current interrupting means for interrupting an energizing circuit from the sealing bottom plate 64 to the sealing upper plate 68 is formed. The lower metal thin plate 65 and the upper metal thin plate 66 are formed with thin portions 65a and 66a, respectively, in a C-shape, and when further pressure is applied, the thin portions 65a and 66a break from the thin portions 65a and 66a to release an abnormal internal pressure to the outside. It also has an explosion-proof valve function to prevent battery rupture due to abnormal internal pressure. Also, the PTC element 67
Regulates the current through self-heating due to an excessive current and a sudden increase in the resistance value when the temperature exceeds a predetermined temperature. Therefore,
When an excessive discharge current flows due to a short circuit or the like, the resistance value can be increased to prevent the excessive current.

[0005] In addition to the functions provided by the secondary battery itself, a protection circuit is provided in the lithium ion secondary battery to prevent overcharge and overdischarge, and this protection circuit is generally provided with a pack. As a form of the battery, the battery is housed and integrated in a case of a battery pack together with a lithium ion secondary battery. 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 is disclosed in JP-A-7-272748,
One disclosed in Japanese Patent Application Laid-Open No. H8-32297 is known.

[0006] The protection circuit can have functions of preventing overcharge and overdischarge, shutting off excessive current, monitoring battery temperature, etc. in addition to the above-described functions. 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 has disclosed in Japanese Patent Application Nos. Hei.
No. 8896. FIG. 13 shows an embodiment of the present invention, in which a battery protection device including the protection circuit 77 is provided in a sealing plate 70 for sealing an open end of a battery case containing a power generation element.

In FIG. 13, a circuit board 71 on which a protection circuit 77 is formed, a PTC element 72 which is a critical temperature resistor for preventing an excessive current such as a short circuit, etc.
A battery protection device provided with a current cut-off mechanism 73 that breaks due to an abnormal increase in battery internal pressure and cuts off the current-carrying circuit and discharges the abnormal internal pressure is provided. The positive electrode of the power generation element is connected to the circuit board 71 through the current interruption mechanism 73 and the PTC element 72.
Are electrically connected from the circuit board 71 to a positive electrode cap 75 serving as a positive electrode input / output terminal of the battery and an S electrode cap 76 for externally connecting the negative side of the protection circuit 77 to the outside. The protection circuit 77 detects states of overcharge, overdischarge, overdischarge current, and the like, and when these states are detected, shuts off the energizing circuit by using the FET as a switching element. Therefore, in this secondary battery, the current interruption mechanism 7
3, since the PTC element 72 and the protection circuit 77 are provided, a triple battery protection function is provided, and the protection circuit can be provided in the battery itself without providing the protection circuit depending on the configuration of the battery pack. it can.

[0009]

However, in the structure of the above-mentioned secondary battery, when the S pole cap 76, the circuit board 71, and the like are caulked and fixed at their peripheral portions by the sealing bottom plate 74, the sealing plate 70 is completed. , Circuit board 71
Also, stress is applied to the protection circuit 77, and when the sealing plate 70 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 77
Is arranged, the deformation space of the current interrupting mechanism 73, which is deformed and ruptured due to abnormal rise of the battery internal pressure, is limited, and there is a problem that it is difficult to obtain the accuracy of the deformation rupture.

In a secondary battery having a high energy density such as a lithium ion secondary battery, a function for setting a temperature range in which charging can be performed and improving safety is provided on the charger side. It is required to provide a temperature detecting terminal for outputting temperature data to the vessel. In the battery pack, a temperature detection terminal is generally provided, and a secondary battery equipped with a battery protection device also has a temperature detection function to enhance the safety in use of the secondary battery. .

An object of the present invention is to provide a secondary battery provided with a protection circuit in the battery and provided with the protection circuit and a temperature detection terminal for outputting temperature data of the secondary battery. .

[0012]

In order to achieve the above object, according to the present invention, 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 provided with a battery protection device. In the secondary battery sealed by the sealing portion, a circuit board having a protection circuit for protecting the battery from overcharging, overdischarging, etc. is provided at the outermost portion of the sealing portion. A positive input / output terminal connected to the positive plate via the protection circuit at the center of the outer surface of the substrate,
An outer cap fitted to the battery case and covering the peripheral portion of the circuit board is joined to the peripheral portion.

According to the above configuration, the secondary battery is provided with a circuit board having a protection circuit in the sealing portion, and the positive electrode plate of the secondary battery is connected to the positive input / output terminal through the protection circuit. The secondary battery is protected from overcharge or overdischarge by the protection circuit, and the secondary battery itself is provided with the protection circuit without forming the battery pack by housing the secondary battery and the protection circuit in the pack case. Therefore, it is possible to improve the versatility of a lithium ion secondary battery or the like, for which provision of a protection circuit is an essential condition, and to make a battery-using device compact.

In the above configuration, a temperature detection terminal is provided on the outer surface side of the circuit board, and a protection circuit and a temperature detection element for detecting the temperature of the battery are provided so as to be connected to the terminal. Since the temperature is output to the temperature detection terminal, the battery-using device or the charger detects the temperature state of the battery from the temperature detection terminal, and can use the battery at an appropriate temperature.

Further, the sealing portion is provided with a current interrupting means for breaking the battery when the internal pressure of the battery rises abnormally and releasing the internal pressure and interrupting the energizing circuit. The protection provided at the sealing portion by the current interrupting means is provided. By configuring the circuit so as to shield the inside of the battery, the protection circuit can be provided in the sealing portion so as not to be affected by the electrolyte solution in the battery case. The current interrupting means breaks when the internal pressure of the battery rises abnormally, discharges gas, and cuts off the power supply circuit to prevent the secondary battery from bursting.

[0016] The sealing portion includes a current interrupting means formed in a disk shape, a PTC formed in a circular ring shape, and an inner cap formed in a hat shape having an open central portion. The overlapped outer peripheral portion is pinched and fixed by the outer peripheral portion of the sealing bottom plate via the inner gasket, and is provided with a protection circuit by joining a spot ring attached to a circuit board to the top of the inner cap, and By configuring the sealing portion to be caulked and fixed to the opening end of the battery case via the outer gasket, a current interrupting means, a PTC for preventing excessive discharge current and a protection circuit can be configured in the sealing portion, The plurality of battery protection devices can ensure safety when the secondary battery is abnormally used or when the device fails.

Further, the spot ring is attached to the circuit board by joining a ring-shaped surface to a conductor pattern formed on the circuit board, and forms a joint surface protruding outside the circuit board from the ring-shaped surface. By mounting the circuit board on the inner cap by joining to the inner cap, the mounting operation of disposing the circuit board in the sealing portion can be easily performed.

Further, the spot ring is made of a copper-nickel alloy or a metal clad material containing a copper-nickel alloy, so that the spot ring can be configured to have excellent bonding properties, conductivity, and corrosion resistance.

An IC formed on the inner surface side of the circuit board
An IC component is mounted on the heat dissipation conductor pattern, the negative electrode connection conductor pattern on the outer surface to which the outer cap is joined and the IC heat dissipation conductor pattern are connected by through holes, and the negative electrode connection conductor pattern and the temperature detection are connected. By arranging a temperature detecting element between the terminal connection conductor pattern and the terminal connection conductor pattern, the heat of the IC component is conducted from the IC heat radiation conductor pattern to the negative electrode connection conductor pattern, and the heat of the battery case is discharged. Since the heat is conducted from the cap to the conductor pattern for connecting the negative electrode, the temperature detecting element connected to the conductor pattern for connecting the negative electrode changes due to the heat of the IC component and the battery case. Since the change in the temperature detecting element can be detected from the temperature detecting terminal joined to the conductor pattern for connecting the temperature detecting terminal, the IC component and the battery can be used at an appropriate temperature.

In addition, a solder resist is applied to a predetermined portion of the circuit board except for a main portion, so that the I.D.
At the C component mounting position, the solder resist is applied in a state where a large number of island patterns are arranged, and an IC is bonded onto the island pattern so that an adhesive is filled between the arrangement of the island resists. By mounting by using the solder resist, the IC component can be insulated from the conductor pattern by the solder resist, the area of the solder resist having low thermal conductivity is reduced, and the IC component is filled with an adhesive between them. Can be conducted to the IC heat dissipation conductor pattern.

Further, by arranging the sides of the regular hexagonal island pattern at predetermined intervals in parallel with the island-like solder resist, the island-like patterns are evenly arranged, and the space for filling the adhesive therebetween is appropriately adjusted. Obtainable.

The temperature detection terminal and the positive electrode input / output terminal are formed by a bridge in which a central temperature detection terminal formed by metal molding and a positive electrode input / output terminal formed with a gap surrounding the central temperature detection terminal are formed thin. After filling the insulating resin between the temperature detecting terminal and the positive electrode input / output terminal by resin molding into the connected and integrated metal parts and joining them together, the bridge is cut off and connected and integrated by the insulating resin. By forming them as terminals, the temperature detection terminal and the positive electrode input / output terminal can be integrated into a composite terminal by insulating with an insulating resin, and can be mounted on a circuit board at the same time.

Further, by forming the top of the temperature detecting terminal at a position lower than the positive electrode input / output terminal, a flat connector is connected to the positive electrode input / output terminal when temperature detection is performed by another means. By doing so, the temperature detection terminal can be not used. Also, when the secondary batteries are connected in series, by providing the same temperature detecting means as described above, the positive electrode input / output terminal makes contact and conduction with the bottom of the battery case, and the temperature detecting terminal can be disabled. .

The outer cap is formed in a bottomed cylindrical shape with a cylindrical portion fitted to the peripheral side surface of the battery case with a metal material, and a bottom portion having an open central portion. A negative electrode connecting piece connected to the negative electrode connecting conductor pattern formed on the circuit board, a board pressing piece for pressing an outer surface side of the circuit board, and an upper surface piece formed at a position deeper than the board pressing piece; The battery case, which is the negative input / output terminal, is connected to the circuit board by forming a resin mold part that exposes the upper surface piece and the outer surface of the circuit board except for the temperature detection terminal and the positive input / output terminal. Along with
The peripheral part of the circuit board located at the outermost part of the sealing part is covered with the resin mold part to prevent the circuit board from being damaged.

By forming a ring-shaped rib in the resin mold portion, it is preferable to prevent a short circuit between the positive electrode input / output terminal and the negative electrode connection piece at the center.

The metal material of the outer cap is formed of a copper-nickel alloy or a metal clad material containing a copper-nickel alloy, so that the outer cap has a bonding property, conductivity, corrosion resistance,
It can be excellent in strength.

Further, by forming openings in the inner cap and the outer cap from the inside of the sealing portion to the outside, when the current interrupting means breaks and the internal pressure is released when the internal pressure of the battery rises abnormally, the gas flows to the outside. A release path can be formed.

[0028]

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.

FIG. 1 is a cross-sectional view of a sealed portion of a secondary battery 1 according to the present embodiment, in which a power generating element is accommodated in a battery case 15 formed in a cylindrical shape with a bottom, and a battery case 15 is formed. By fixing the sealing portion 8 to the opening end side via the outer gasket 13 by caulking, the battery case 15
Is configured such that the open end of the is closed. The illustration of the inside of the battery case 15 accommodating the power generation element 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.

The sealing portion 8 includes a sealing bottom plate 17, a lower metal thin plate 22 and an upper metal thin plate 23 forming current interrupting means, and a PTC element 21 formed in a circular ring shape and forming an excessive current preventing means from the inside of the battery. , An inner cap 18 supporting the circuit board 10, and a circuit board 10 forming an electronic circuit forming a protection circuit. The sealing portion 8 is formed in a disk shape to seal the open end of the cylindrical battery case 15 with a bottom, and each component is also formed in a circular shape. The lower metal thin plate 22, the upper metal thin plate 23, the PTC element 21, and the inner cap 18 are laminated at their peripheral portions,
The peripheral portion of the sealing bottom plate 17 is fixed by pressure through an inner gasket 19, and the circuit board 10 is mounted on the inner cap 18 via a spot ring 11. 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.

After the open end of the battery case 15 is sealed by the sealing portion 8 configured as described above, the outer cap 20 is placed on the open end side of the battery case 15 so as to wrap the outer peripheral portion of the circuit board 10. Cover the outer cap 20
Is bonded to the circuit board 10 and the battery case 15 to complete the secondary battery 1 including the battery protection device.

In the above configuration, the positive and negative plates of the positive and negative electrodes accommodated in the battery case 15 are lead-connected to the sealing bottom plate 17, and the sealing bottom plate 17, the lower metal thin plate 22, and the lower metal thin plate 22 are connected.
A, the upper metal sheet 23, PT
The C element 21, the inner cap 18, the spot ring 11, the protection circuit formed on the circuit board 10, and the positive input / output circuit connected to the positive input / output terminal 2 joined to the outer surface of the circuit board 10 are formed. In addition, since the negative plate of the positive and negative plates is connected to the battery case 15, the battery case 15 serves as a negative electrode input / output terminal, and the negative electrode of the secondary battery is connected to the circuit board 10 by the outer cap 20 joined to the battery case 15. Connected.

The inside of the sealing portion 8 is formed by the lower metal sheet 2.
2 and the upper metal thin plate 23 shield the inside of the battery case 15, so that the circuit board 10 and other components may cause dielectric breakdown, corrosion, or the like due to the electrolyte or the vaporized gas injected into the battery case 15. Affected is prevented.

Next, details of each component will be described. The configuration of the current interrupting means by the lower metal thin plate 22 and the upper metal thin plate 23 and the configuration of the excessive current regulating means by the PTC element 21 are the same as those of the conventional configuration, and the description thereof will be omitted.

FIG. 2 shows the inner surface 10a of the circuit board 10.
And conductor patterns formed on the outer surface side 10b. The conductor patterns on both surfaces are connected by through holes 40 at essential parts. As shown in FIG.
A circuit pattern for mounting an electronic component such as an IC component to form a protection circuit is formed at a central portion of the sealing bottom plate 1a.
7, lower metal sheet 22, upper metal sheet 23, PTC element 2
1, a conductor pattern 2 for connecting the positive electrode to the positive electrode of the power generating element through the inner cap 18 and the spot ring 11
9 are formed. Also, as shown in FIG.
A conductor pattern 30 for connecting a temperature detection terminal and a conductor pattern 31 for connecting a positive electrode input / output terminal are formed in a central portion of the outer surface side 10b so as to surround the conductor pattern. Patterns 32, 32 and a conductor pattern 33 for inspection for performing an operation test of the circuit board 10 are formed.

As shown in FIG. 3, the circuit board 10 has a solder resist 9
(Shown with diagonal lines). This solder resist 9 is generally applied for the purpose of preventing soldering failure such as a solder bridge, preventing insulation deterioration between conductor patterns, preventing corrosion of the conductor pattern surface, and the like. Plays an additional role in the configuration of. That is, at the center of the inner surface 10a of the circuit board 10, the bare chip I
The C component 5 (see FIG. 4) is mounted. At this mounting position, the IC heat dissipation conductor pattern connected through the through hole 40 to the negative electrode connection conductor pattern 32 on the outer surface 10b because of the need for temperature detection described later. 34, it is necessary to mount the IC component 5 insulated therefrom.
The solder resist 9 plays a role in maintaining the insulation between the IC component 5 and the IC heat dissipation conductor pattern 34. However, since the solder resist 9 has low thermal conductivity, the heat radiation of the IC component 5 is impaired. Therefore, as shown in FIG. 3A, the formation of the solder resist 9 at the mounting position of the IC component 5 is performed in a state of a hexagonally arranged resist 9a in which hexagonal shapes are arranged. When the IC component 5 is bonded by applying an adhesive on the hexagonal array resist 9a, the adhesive is filled while the hexagonal array resist 9a is arrayed, and the IC component 5 is thermally conductive through the adhesive. Is dissipated to the IC heat dissipation conductor pattern 34, and the IC component 5 has the hexagonal arrangement resist 9a to secure insulation and at the same time to obtain heat dissipation through the adhesive. The hexagonal array resist 9a may be an array of another shape, but the hexagonal array is easy to arrange uniformly, and the area where the hexagonal array resist 9a does not exist in the space of the mounting position of the IC component 5, that is, the area occupied by the adhesive Can be sufficiently secured.

Circuit board 10 provided with solder resist 9
As shown in FIG. 4, the inner side 10a has the I
The C component 5 and the electronic component 14 are mounted, and the thermistor (temperature detecting element) 12 is mounted on the outer surface 10b by connecting between the temperature detecting terminal connecting conductor pattern 30 and the negative electrode connecting conductor pattern 32. The IC component 5 adhered on the hexagonal array resist 9a is wired and connected by wire bonding as shown in the figure, and the electronic component 14 and the thermistor 1 are connected.
2 is connected by soldering. Furthermore, the inner side 10a
Spot ring 1 on the positive electrode connecting conductor pattern 29
1 are joined by soldering. This soldering
Openings 11b, 11b formed in spot ring 11
This is done by soldering the spot ring 11 to the portion of the positive electrode connecting conductor pattern 29 exposed below the portion where the solder resist 9 is not applied. The spot ring 11 is made of a copper-nickel alloy (Cu55% -Ni45
%) Or a metal clad material containing a copper-nickel alloy is preferable because of its excellent bonding property, conductivity and the like. In addition, the conductor pattern 30 for connecting the temperature detection terminal and the conductor pattern 31 for connecting the positive electrode input / output terminal on the outer surface 10b.
6, a composite terminal 4 in which the positive electrode input / output terminal 2 and the temperature detection terminal 3 are integrated is joined.

The composite terminal 4 is formed by integrally molding the temperature detection terminal 3 and the positive electrode input / output terminal 2 by metal molding and resin molding. As shown in FIG. 5, a metal part 6 formed by connecting the central temperature detection terminal 3 and the positive electrode input / output terminal 2 outside thereof by bridges 41, 41 which are formed to be thin, is formed by metal molding. Is done. This metal part 6
In the space between the temperature detection terminal 3 and the positive electrode input / output terminal 2
As shown in FIG. 6, the insulating resin 7 is filled by resin molding, and the bridges 41, 41 are cut off, so that the positive input / output terminal 2 and the temperature detecting terminal 3 are electrically insulated by the insulating resin 7. Both are connected to each other by an insulating resin 7 to form an integrated composite terminal 4.

The temperature detecting terminal 3 constituting the composite terminal 4
As shown in FIG. 6, the temperature detection can be arbitrarily disabled and used by configuring the top portion to be lower than the top portion of the positive electrode input / output terminal 2 as shown in FIG. That is, in the case of a configuration in which the secondary batteries 1 are connected in series, a positive electrode input / output terminal 2 is connected to the bottom of the battery case 15 of one , The temperature detection terminal 3 located at a position lower than the positive electrode input / output terminal 2 is in a non-contact state,
The function of the temperature detection can be invalidated. Also,
Even when used alone, the use of the temperature detection terminal 3 can be invalidated by connecting a flat contact to the positive electrode input / output terminal 2.

Conversely, if a composite connector having a coaxial structure in which a connector to the temperature detecting terminal 3 is formed at the center position and a connector to the positive electrode input / output terminal 2 is formed around the central connector, the positive electrode input / output terminal 2 and the temperature detection terminal 3 can be connected simultaneously. In addition, since the negative electrode connection portion is formed on the outer cap 20 to be described later on the same surface side as the positive electrode input / output terminal 2 and the temperature detection terminal 3, the connection of the positive electrode, the negative electrode, and the temperature detection of the secondary battery 1 is made in one direction. And the structure of the battery connection of the device can be simply configured.

The circuit board 10 formed as described above
As shown in FIG. 1, the attached spot ring 11
Are fixed to the outermost part of the sealing portion 8 by joining the both end projections 11a, 11a to the inner cap 18 by spot welding. As shown in FIG. 7, the inner cap 18 has a hat-shaped top formed with an opening 18 b for allowing a circuit component mounted on the circuit board 10 to escape, and a flat surface formed around the opening 18 b. The spot ring 11 is spot-welded to the portion 18c. In addition, inner cap 1
A plurality of exhaust holes 18a are formed around 8.

The sealing portion 8 having the above-described structure is fixed to the opening end of the battery case 15 via the outer gasket 13 to seal the opening end of the battery case 15. On the open end side of the battery case 15 sealed by the sealing portion 8,
As shown in FIG. 1, the outer cap 20 is covered. As shown in FIG. 9, the outer cap 20 has a cylindrical portion having a bottomed cylindrical shape fitted into the battery case 15, a bottom portion connected to the circuit board 10 with a metal portion, and a circuit portion with a resin portion. It is configured so as to cover the outer surface side excluding the terminal portion of No. 10.

FIG. 8 shows the metal member 2 of the outer cap 20.
4 shows a copper-nickel alloy (Cu 55%-
A metal-clad material containing Ni45%) or a copper-nickel alloy is press-formed to form a bottomed cylindrical bottom in a three-stage structure, and diametrically opposed to an intermediate height position to form negative electrode connecting pieces 25, 25. A plurality of substrate pressing pieces 26 are formed at the same height as the negative electrode connecting piece 25, and a plurality of upper surface pieces 27 are formed at positions deeper than the substrate pressing pieces 26. Exhaust holes 36 are formed at the position of the upper surface piece 27, and cutouts 28 are formed at a plurality of positions in the cylindrical portion, so that the fitting to the battery case 15 is improved.

As shown in FIG. 9, a resin molded portion 38 is formed on the bottom of the metal member 24 having the above-described structure by resin molding, so that a bottom surface having a terminal through hole 37 in the center is formed. The resin molded part 38 forms a negative electrode opening 43 on the negative electrode connecting piece 25 together with the terminal through hole 37, passes the composite terminal 4 through the terminal through hole 37, and connects the negative electrode connecting piece 25 from the negative electrode opening 43. Circuit board 10
It is configured so that it can be joined to the upper negative electrode connecting conductor pattern 32. In addition, a rib 39 is formed in a ring shape at a portion other than the negative electrode opening 43 to prevent a short circuit between the positive electrode and the negative electrode.

The negative electrode connecting piece 2 viewed from the negative electrode opening 43
5 and the conductor pattern 32 for connecting the negative electrode on the circuit board 10 are joined by means such as ultrasonic welding. The negative electrode connecting piece 25 viewed from the negative electrode opening 43 can be used as a negative electrode input / output terminal of the secondary battery 1 from the device side. In this case, the negative electrode contact piece is in contact with the positive electrode input / output terminal 2 and the temperature detection terminal 3 on the same surface side. And the connection structure of the device to the secondary battery 1 can be easily configured. Incidentally, the negative electrode connection to the device side of the secondary battery 1 is usually made at the outer peripheral portion of the bottom of the metal member 24 (the top of the whole battery) or at the bottom of the battery case 15.

FIG. 10 shows the configuration of the secondary battery 1 described above as an electric circuit diagram.
The negative electrode plate of the power generation element 51 housed in the battery case 15
To be a negative input / output terminal. On the other hand, the positive electrode plate of the power generation element 51 includes the lower metal sheet 22 and the metal sheet 23.
Connected to the protection circuit on the circuit board 10 through the PTC element 21 and the control circuit 5.
It is connected to the positive electrode input / output terminal 2 through the FET 52 whose ON / OFF is controlled by 0. Further, a thermistor 12 mounted on the outer surface of the circuit board 10 is connected to the temperature detection terminal T.

The current interrupting means in the above configuration shields the inside of the battery and the inside of the sealing portion 8 to prevent components such as the circuit board 10 formed in the sealing portion 8 from coming into contact with the electrolytic solution. The inside of the battery is prevented from communicating with the outside air.
On the other hand, when the internal pressure of the battery rises abnormally due to the gas generated by the decomposition of the electrolytic solution due to abnormal use, when the welding point A between the lower metal thin plate 22 and the upper metal thin plate 23 peels off due to the abnormal internal pressure, Cut off. As the deformation proceeds, the lower metal thin plate 22 and the upper metal thin plate 23 break from the easily breakable portion 22a formed in a C-shape and the abnormal internal pressure is released to the outside. Lower metal sheet 22 and upper metal sheet 2
The gas in the battery released by the breaking of 3 is exhausted to the outside because the exhaust hole 18a is formed in the inner cap 18 and the exhaust hole 36 is formed in the outer cap, thereby preventing the battery from being broken. Each of the exhaust holes 18a and 36 is in a direction intersecting with the direction of discharging the gas emission fumes, so that the risk of the battery jumping out due to the gas discharge force is prevented.

Further, the PTC element 21 self-heats due to an excessive current due to a short circuit of the secondary battery 1 and rises in temperature. When the PTC element 21 reaches a predetermined critical temperature, its resistance value sharply increases and regulates discharge of the excessive current. To prevent battery damage.

When the control circuit 50 detects a voltage in an overcharge state or an overdischarge state and an overdischarge current, the protection circuit formed on the circuit board 10
Is turned off to shut off the current-carrying circuit to protect the secondary battery 1 from overcharge, overdischarge, and overdischarge current.

The thermistor 12 is provided with an IC heat dissipation conductor pattern 34 on which the IC component 5 is mounted and a through hole 4.
The resistance value of the IC component 5 is changed by the conduction of heat of the IC component 5 by being connected to the negative electrode connection conductor pattern 32 connected by 0 and mounted on the opposite surface of the IC component 5. It can be detected from the detection terminal 3. Further, since the negative electrode connecting conductor pattern 32 to which the thermistor 12 is joined is connected to the battery case 15 through the outer cap 20, the temperature of the battery case 15, that is, the secondary battery 1 is conducted, and the resistance value changes according to the temperature. Then, similarly, a change in the resistance value can be detected from the temperature detection terminal 3. Therefore, from the temperature detection terminal 3 to the IC component and the secondary battery 1
For example, when the charger conducts charging while detecting the temperature by conducting contact with the temperature detection terminal 3, the state of the secondary battery 1 can be detected from the temperature, and a predetermined temperature range can be detected. Control for executing charging can be performed.

As in the configuration of each embodiment described above,
If a protection circuit is provided in the battery, the function of preventing an excessive discharge current can be provided by the configuration of the electronic circuit 11. Therefore, the provision of the PTC element 21 having a function of preventing an excessive discharge current due to a short circuit or the like is eliminated. You can also. That is, as a function of the electronic circuit 11, there is a function of detecting an excessive current, and when the function is detected, the energizing circuit is shut off.
The PTC element 21 can be eliminated.

The configuration of each of the above-described embodiments is formed to have substantially the same outer dimensions as those of a conventional lithium ion secondary battery without a protection circuit. FIG. 11 shows the secondary battery 1 shown in the present embodiment and the secondary battery P without a conventional protection circuit shown in FIG.
For the same battery capacity, the diameter and the upper and lower dimensions are substantially the same. Therefore, although the battery accommodating space of the device using the battery power supply is the same, the form conventionally formed as a pack battery for forming the protection circuit becomes unnecessary, and the accommodating space of the battery power supply can be reduced, and the equipment can be reduced. This can contribute to miniaturization and weight reduction.

[0053]

As described above, according to the present invention, the protection circuit for protecting the battery from overcharge or overdischarge can be provided in the secondary battery with a simple structure, so that the protection can be performed without forming a battery pack. A secondary battery provided with a circuit can be configured. In addition, since the secondary battery can be formed in the same size as a conventional secondary battery without a protection circuit, a form in which a protection circuit is conventionally provided as a pack battery is unnecessary,
The space for accommodating a battery that uses a secondary battery as a power source 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 cross-sectional view illustrating a configuration of a secondary battery according to an embodiment.

FIGS. 2A and 2B are plan views showing a conductor pattern formed on a circuit board, wherein FIG. 2A is an inner surface side and FIG.

FIGS. 3A and 3B are plan views showing a solder resist applied on a circuit board, wherein FIG. 3A is an inner surface side and FIG.

FIGS. 4A and 4B are plan views showing an inner surface side and an outer surface side, respectively, showing a state where an electronic component is mounted on a circuit board and a spot ring is mounted.

5A is a plan view showing a configuration of a metal part for forming a composite terminal, FIG. 5B is a sectional view taken along line BB of FIG.
(C) is a sectional view taken along line CC.

6A is a plan view showing a configuration of a composite terminal, and FIG.
Is a sectional view taken along line DD, and FIG. 3C is a sectional view taken along line EE.

7A is a plan view showing a configuration of an inner cap, FIG.
(B) is a side view.

8A is a plan view, FIG. 8B is a side view, and FIG. 8C is a cross-sectional view taken along line FF of the metal member forming the outer cap.

9A is a plan view showing the configuration of the outer cap, FIG.
(B) is a side view, and (c) is a sectional view taken along line GG.

FIG. 10 is an electric circuit diagram of a secondary battery according to the embodiment.

FIG. 11 is a cross-sectional view comparing the secondary battery according to the embodiment with a conventional secondary battery.

FIG. 12 is a cross-sectional view illustrating a configuration of a conventional secondary battery.

FIG. 13 is a cross-sectional view of a secondary battery including a conventional protection circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Secondary battery 2 Positive electrode input / output terminal 3 Temperature detection terminal 4 Composite terminal 5 IC part 6 Metal part 7 Insulating resin 8 Sealing part 9 Solder resist 10 Circuit board 11 Spot ring 12 Thermistor (temperature detection element) 13 Outer gasket 15 Battery case DESCRIPTION OF SYMBOLS 17 Sealing bottom plate 18 Inner cap 19 Inner gasket 20 Outer cap 21 PTC element 22 Lower metal thin plate 23 Upper metal thin plate 24 Metal member 25 Negative electrode connection piece 26 Substrate holding piece 27 Upper surface piece 29 Conductor pattern for positive electrode connection 30 Conductor for temperature detection terminal connection Pattern 31 Conductor pattern for connecting the positive electrode input / output terminal 32 Conductor pattern for connecting the negative electrode 34 Conductor pattern for heat dissipation of IC 38 Resin molded part 39 Rib 40 Through hole 41 Bridge

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-169506 (JP, A) JP-A-7-272748 (JP, A) JP-A 8-31460 (JP, A) 145766 (JP, U) WO 98/1913 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 10/40-10/48 H01M 2/34

Claims (15)

(57) [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 portion provided with a battery protection device. A protection circuit for protecting the battery from overcharging, overdischarging, etc. is provided at the outermost part of the circuit board, and a circuit board is provided on the inner surface thereof. A secondary battery comprising: a positive electrode input / output terminal connected to a positive electrode plate; and an outer cap which is fitted to the battery case and covers a peripheral portion of the circuit board. 2. The secondary battery according to claim 1, wherein a temperature detection terminal is provided on an outer surface side of the circuit board, and a protection circuit connected to the temperature detection terminal and a temperature detection element for detecting a temperature of the battery are provided. 3. The sealing portion is provided with a current interrupting means for breaking the battery when the internal pressure of the battery rises abnormally and releasing the internal pressure and interrupting the energizing circuit, and the protection provided in the sealing portion by the current interrupting means. 3. The secondary battery according to claim 1, wherein the secondary battery is configured to shield a circuit from the inside of the battery. 4. The sealing part includes a current interrupting means formed in a disk shape, a PTC formed in a circular ring shape, and an inner cap formed in a hat shape with an open central portion. The overlapped outer peripheral portion is pinched and fixed by the outer peripheral portion of the sealing bottom plate via the inner gasket, and is provided with a protection circuit by joining a spot ring attached to a circuit board to the top of the inner cap, and The secondary battery according to any one of claims 1 to 3, wherein the sealing portion is caulked and fixed to an open end of the battery case via an outer gasket. 5. A spot ring is attached to a circuit board by joining a ring-shaped surface to a conductor pattern formed on a circuit board, and forms a joint surface protruding outward from the circuit board from the ring-shaped face. 5. The secondary battery according to claim 4, wherein the secondary battery is configured to fix the circuit board on the inner cap by joining to the inner cap. 6. The secondary battery according to claim 4, wherein the spot ring is formed of a copper-nickel alloy or a metal clad material containing a copper-nickel alloy. 7. A negative electrode connection conductor pattern on an outer surface to which an IC component is mounted on an IC heat radiation conductor pattern formed on an inner surface of a circuit board and to which an outer cap is joined, and the IC.
The heat radiation conductor pattern is connected by a through hole, and a temperature detection element is provided between the negative electrode connection conductor pattern and the temperature detection terminal connection conductor pattern. Rechargeable battery. 8. A solder resist is applied to a predetermined portion of the circuit board except for the main part, and the solder resist is applied to a mounting position of the IC component on the conductor pattern for heat dissipation of the IC in a state where a large number of island patterns are arranged. 8. The secondary battery according to claim 7, wherein an IC component is mounted on the island pattern by bonding so that an adhesive is filled between the arrangement of the island-shaped solder resists. 9. The secondary battery according to claim 8, wherein the island-shaped solder resist is formed by arranging the sides of a regular hexagonal island pattern in parallel at predetermined intervals. 10. A temperature detection terminal and a positive electrode input / output terminal,
The temperature detection terminal at the center by metal molding and the positive electrode input / output terminal formed with a gap surrounding it are connected and integrated by a thin-walled bridge. The secondary battery according to claim 1, wherein after filling an insulating resin between the positive electrode input / output terminals and joining the two, the bridge is cut off to form a composite terminal which is connected and integrated by the insulating resin. . 11. The secondary battery according to claim 10, wherein the top of the temperature detection terminal is located at a position lower than the positive electrode input / output terminal. 12. The outer cap is formed in a bottomed cylindrical shape having a cylindrical portion fitted to the peripheral side surface of the battery case with a metal material, and a bottom portion having an open central portion. A negative electrode connecting piece connected to the negative electrode connecting conductor pattern formed on the circuit board, a board pressing piece for pressing an outer surface side of the circuit board, and an upper surface piece formed at a position deeper than the board pressing piece; 3. The secondary battery according to claim 1, further comprising: a resin mold portion that exposes the upper surface piece and covers an outer surface of the circuit board except for the temperature detection terminal and the positive electrode input / output terminal. 4. 13. The secondary battery according to claim 12, wherein a rib is formed in the resin mold portion in a ring shape. 14. The secondary battery according to claim 12, wherein the metal material of the outer cap is a copper nickel alloy or a metal clad material containing a copper nickel alloy. 15. An inner cap and an outer cap each having an opening formed from the inside of the sealing portion to the outside.
15. The secondary battery according to any one of 14 above.