JP4734868B2 - Secondary battery with battery protection circuit - Google Patents

Description

  The present invention is a secondary battery such as a lithium ion secondary battery provided with a battery protection circuit and configured to have a function of protecting the battery itself from overcharge, overdischarge, etc. The present invention relates to a secondary battery including a battery protection circuit that can be applied to a battery.

  The secondary battery has various protection functions to prevent damage to the battery due to abnormal use such as short circuit of the battery peripheral circuit, short circuit between the positive and negative electrodes, overcharge and overdischarge of equipment using this secondary battery. It has been. These include PTC elements that block excessive discharge current due to short circuits, etc., and current cut-off valves that release the internal pressure by shutting off the energization circuit due to abnormal rise in battery internal pressure due to overcharging. This is a well-known function to equip. In addition, a lithium ion secondary battery is provided with a battery protection circuit in order to prevent overcharge, overdischarge, etc., and this battery protection circuit is generally in the form of a battery pack. The formed circuit board is accommodated in the pack case and integrated. It is well known that a battery pack in which such a secondary battery and a battery protection circuit are housed and integrated in a pack case is often used as a battery power supply device for portable devices such as a mobile phone and a portable computer. By the way.

Since the battery protection circuit has functions such as overcurrent blocking and battery temperature monitoring in addition to the above-described overcharge and overdischarge prevention, if the battery can be mounted integrally with the secondary battery itself, A secondary battery provided with a battery protection circuit can be formed without forming a pack, and means for that is disclosed (for example, see Patent Documents 1 and 2).
JP-A-8-31460 Japanese Patent Laid-Open No. 11-26029

  However, in order to integrate the secondary battery and the battery protection circuit, the connection plate joined to the protruding terminal of the secondary battery and the lead plate joined to the battery can are respectively connected to the metal connection pads on the protection circuit board. Must be joined. When the conductor pattern of the circuit board and the back surface of the connection pad are bonded by solder bonding or a conductive adhesive, and the connection plate and the lead plate are bonded to the surface of the connection pad by laser welding, resistance welding, or soldering There was a problem that the connection pad was displaced from a predetermined position due to the heat and the reliability was lowered.

  The present invention solves such a conventional problem. The connection plate joined to the projecting terminal of the secondary battery and the lead plate joined to the battery can are each reliably connected to the metal connection pad on the protection circuit board. It aims at providing the secondary battery provided with the battery protection circuit joined in a high state.

In order to achieve the above object, the present invention provides a battery can in which a power generation element is housed in a bottomed cylindrical container, and is provided insulated from the battery can at the center of a sealing portion that seals the open end of the battery can. A battery protection circuit that protects the secondary battery from overcharge, overdischarge, etc. and a plurality of input / output terminals are integrally provided on a secondary battery in which a positive electrode or a negative electrode is respectively set on the projecting terminal. The battery protection circuit board is provided on the sealing portion side of the battery can, and the connection plate joined to the protruding terminal and the lead plate joined to the battery can are respectively input / output terminals on the battery protection circuit board. Connected to a connection pad connected by soldering or conductive adhesive, an upper insulating holder having an opening formed in the input / output terminal portion is provided to cover the circuit board and to insulate the secondary battery. Constructed by covering with a sheet A secondary battery comprising,
The conductor pattern of the protection circuit board and the back surface of the metal connection pad are partially bonded, and the connection plate and the lead plate are bonded to the surface of the connection pad other than the bonded portion. The protective circuit board and the connection pad are preferably joined at the four corners on the back surface of the connection pad or at the edges including the four corners on the back surface of the connection pad.

According to the present invention, the protective circuit board and the back surface of the connection pad are partially bonded, and the connection plate and the lead plate are bonded to each other on the surface of the connection pad other than the bonded portion. Therefore, the solder or the conductive adhesive is remelted by heat when the connecting plate and the lead plate and the connecting pad are joined by laser welding, resistance welding, or soldering, and the conductor pattern of the protective circuit board A secondary battery provided with a battery protection circuit that does not cause a positional deviation with respect to the connection pad or short-circuits with other protection circuit board conductor portions can be configured.

  The upper insulating holder further includes a connecting portion formed at the ends of a pair of extending portions extending toward the bottom surface side of the battery can. The bottom surface side of the battery can covers the bottom surface of the battery can. A lower insulating holder having a connecting portion formed at the tip of a pair of extending portions extending toward the sealing portion side of the battery can is arranged to connect the upper insulating holder and the lower insulating holder between the connecting portions. In addition, the side peripheral surface of the secondary battery including the side peripheral parts of the upper insulating holder and the lower insulating holder is covered with an insulating sheet, thereby providing a space in which the circuit board can be disposed on the sealing part of the secondary battery. Thus, a secondary battery including a battery protection circuit can be configured without damaging the form of the secondary battery.

  In addition, when a spacer that forms a seating surface of the protection circuit board and is separated from the secondary battery is disposed, the circuit board is disposed on the secondary battery via the spacer, and the connection plate and Since the secondary battery is connected to the battery protection circuit configured on the circuit board by the lead plate, the secondary battery is provided with a battery protection circuit connected to the input / output terminal formed on the circuit board through the battery protection circuit. It is formed in a secondary battery. A secondary battery with a battery protection circuit in which only the input / output terminals are exposed to the outside is compactly configured by insulatingly covering all parts except the input / output terminals with the upper insulating holder, lower insulating holder and insulating sheet. Is done.

  In the above configuration, it is preferable to apply to a secondary battery in which protruding terminals are formed in an oval shape, and it can be applied as a battery power source of a portable device that is aimed at downsizing and thinning.

  In addition, the electronic component mounted on the sealing part side of the circuit board is disposed at a position corresponding to the recess formed on the sealing part of the secondary battery, thereby reducing the amount of protrusion from the secondary battery. A protection circuit can be provided.

  In addition, the spacer is positioned at the time of mounting on the secondary battery by forming a positioning portion for the secondary battery and an opening at a position corresponding to the electronic component mounted on the circuit board. The battery protection circuit can be accommodated in a small space by storing the electronic component mounted on the sealing portion side of the substrate in the opening.

  By forming the positioning portion on positioning protrusions arranged in parallel to both sides of the protruding terminal, it is possible to reinforce insulation between the battery can and the connection plate simultaneously with positioning.

  Further, the reverse loading can be prevented by arranging the plurality of input / output terminals provided on the circuit board asymmetrically.

  Further, when the upper insulating holder and the lower insulating holder are connected by overlapping and / or engaging the respective connecting portions, the connection is ensured.

  Since the battery protection circuit is configured integrally with the secondary battery, it can be used as if only the battery is loaded into the device without providing a battery pack configuration, and the size of the device that uses the secondary battery as a power source Can contribute to reduction in weight and weight. In addition, by improving the function of the battery protection circuit, it is possible to protect the secondary battery from overcharge, overdischarge, overcurrent, etc. without providing a PTC element or a current shutoff valve, and it is reliable without reducing the capacity of the secondary battery. A highly functional battery protection function can be configured in a compact manner.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.

  In the embodiment shown below, a circuit board constituting a battery protection circuit for protecting a secondary battery from overcharge, overdischarge, etc. is integrally attached to a flat lithium ion secondary battery as shown in FIG. As shown in FIG. 1, the secondary battery is configured as a secondary battery provided with a battery protection circuit without impairing the form of the secondary battery.

  In FIG. 1, the secondary battery including the battery protection circuit according to the present embodiment exposes the positive terminal 4, the negative terminal 5, and the temperature detection terminal 6 to the outside on one end face, and all the upper insulation except for this terminal part. The secondary battery 1 and the circuit board 9 constituting the battery protection circuit are integrally incorporated in the holder 13, the lower insulating holder 14, and the insulating label 7.

  FIG. 2 is an exploded view of the internal structure of the secondary battery 1 configured as a lithium ion secondary battery. The secondary battery 1 has a positive input / output terminal (projecting terminal) 25 on the sealing portion side. A connecting plate 11 to be joined, a spacer 12 disposed on the secondary battery 1 to provide a seating surface of the circuit board 9, a battery protection circuit and a positive electrode terminal 4, a negative electrode terminal 5 and a temperature detection terminal 6 are formed. The upper insulating holder 13 for insulatingly covering the upper side of the circuit board 9 is disposed, the base 10b is joined to the bottom of the secondary battery 1 and the bottom of the secondary battery 1, and the lead part 10a is connected to the sealing part A pair of extending lead plates 10 and 10 and a lower insulating holder 14 for insulatingly covering the lower side are disposed.

  As shown in FIG. 3, the secondary battery 1 houses a power generation element 33 in a battery can 31 formed in a bottomed cylindrical shape with an oval cross section, and a gasket 35 and a sealing plate 32 at the open end of the battery can 31. And the sealing part provided with the electrode cap 34 is arranged, and the opening part of the battery can 31 is sealed and formed into a small and flat shape by joining the sealing part by caulking processing that bends the opening end inward. The positive electrode plate constituting the power generation element 33 is connected to the electrode cap 34 insulated from the battery can 31 by the gasket 35, and the central protrusion serves as the positive electrode input / output terminal 25 of the secondary battery 1. The negative electrode plate constituting the power generation element 33 is connected to the battery can 31, and the battery can 31 serves as a negative electrode input / output terminal of the secondary battery 1.

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

Further, a spacer 12 formed as shown in FIG. 4 is attached to the sealing portion side of the secondary battery 1. As shown in FIG. 4B, a pair of positioning portions 37 are formed on the lower surface (secondary battery 1 side) of the spacer 12 so as to contact the longitudinal side surface of the positive electrode input / output terminal 25 formed in an oval shape. The spacer 12 is positioned and fitted on the secondary battery 1 by being disposed on the sealing portion so as to be fitted to the positive input / output terminal 25, and is insulated from the battery can 31 serving as the negative electrode. Sexuality is strengthened.

  The connection plate through hole 38 opened between the pair of positioning portions 37 allows the lead portion 11a of the connection plate 11 joined to the positive input / output terminal 25 to penetrate the upper surface. A seat surface insulated from the secondary battery 1 is formed by the spacer 12, and openings 36 a and 36 b for accommodating electronic components mounted on the sealing portion side of the circuit board 9 are formed on the seat surface. When the circuit board 9 is arranged on this, the electronic components mounted on the sealing part side are accommodated in the openings 36a and 36b, so that the circuit board 9 adds the thickness of the board and the thickness of the spacer 12. It becomes the state laminated | stacked on the secondary battery 1 only by height, and the increase in height by providing a battery protection circuit is suppressed.

  FIG. 5 is a perspective view of circuit patterns formed on the front and back surfaces of the circuit board 9 and electronic components mounted on the circuit pattern. The battery protection circuit and input / output terminals shown in FIG. Is configured. As shown in FIG. 5, a battery protection circuit in which IC components 21 and 22 and a chip component 26 are mounted is formed on the back surface side (b) of the circuit board 9, and the positive electrode terminal 4 is formed on the front surface side (a). The negative electrode terminal 5 and the temperature detection terminal 6, the connection plate conductor pattern 15 for connecting the connection plate 11, and the lead plate conductor patterns 16a and 16b for connecting the lead plate 10, are formed. Such circuit patterns formed on both surfaces are connected by through holes 30 at important points.

  The conductive pattern 15 and the back surface of the metal connection pad 51 are joined by soldering at the four corners 51 a, 51 b, 51 c, 51 d of the back surface, and from the lead through holes 20 formed in the circuit board 9. The lead portion 11a is passed through the lead portion 11a of the connection plate 11, the lead portion 11a is bent on the front surface 51e of the connection pad, and resistance welding is performed at the central portion where the back surface of the connection pad is not joined.

  In addition, the conductive patterns 16a and 16b and the back surfaces of the metal connection pads 52 and 53 are joined by a conductive adhesive at edges 52a, 52b, 53a, and 53b including the four corners of the back surfaces. The lead portions 10a and 10a of the pair of lead plates 10 are passed through the lead plate passage recesses 29 and 29 formed at both ends of the circuit board 9 on the surfaces 52c and 53c, respectively, and bent on the connection pad surfaces 52c and 53c, respectively. Thus, the back surface of the connection pad is joined by soldering at the unjoined center portion.

  The reason for forming a metal connection pad on the conductive pattern is that when the lead part is joined directly to the conductive pattern, the conductive pattern is a very thin copper foil, so that part of the conductive pattern may be burned out by heat during welding. This is because there is an effect of preventing a short circuit caused by a solder ball at the time of soldering, and a highly reliable secondary battery can be configured. As a material of the connection pad, a nickel plate or a steel plate whose surface is nickel-plated is preferable.

  By joining the lead part to the surface of the connection pad where the conductive pattern and the metal connection pad are not bonded in this way, the thermal energy of laser welding, resistance welding, and soldering is reduced. Stable joining is possible because it does not escape through the joint.

  Next, after the connection plate 11 and the lead plate 10 are bonded to the connection pads 52 and 53, the circuit board 9 is bonded onto the spacer 12.

The battery protection circuit shown in FIG. 6 includes a main control circuit IC21 that protects the secondary battery 1 from overcharge, overdischarge, and overcurrent. When a voltage in an overcharge, overdischarge, and overcurrent state is detected, The switching element incorporated in the IC is controlled to be in an off state, the off state is maintained until a predetermined release voltage is detected by a hysteresis operation, the input / output circuit of the secondary battery 1 is shut off, and the secondary battery 1 is Prevent overcharge, overdischarge and overcurrent. Further, control is performed so that energization is possible in the discharging direction when the input / output circuit is interrupted due to overcharge, and energization is possible in the charging direction when the input / output circuit is interrupted due to overdischarge. In addition to the main control circuit IC22, a sub-control circuit IC21 that protects the secondary battery 1 from overcharging is provided. The sub-control circuit IC21 always controls the switching element incorporated in the IC to be in an ON state to keep the input / output circuit in a conductive state, and when the operation of the main control circuit IC22 is not performed to prevent overcharge. The progress of the overcharge state is detected, the switching element is controlled to be turned off, the input / output circuit is shut off, the off state is maintained until a predetermined release voltage is detected by the hysteresis operation, and the secondary battery 1 is overloaded. Prevent damage due to the progress of charging. With this configuration, the secondary battery 1 is doubly protected from overcharging, and in particular, the secondary battery 1 that is significantly damaged by overcharging can be protected by the battery protection circuit. Therefore, the current cutoff valve and PTC (Positive Temperature Coefficient) that are conventionally provided in the battery to protect the battery can be eliminated, and the size and thickness are reduced as applied to this embodiment. This is a suitable means for the secondary battery 1. In other words, it is difficult to obtain a space for providing a current cutoff valve or PTC in a small or thin battery, and the provision of these reduces the volume of the positive and negative electrode plates serving as a power generation element, and the battery performance must be reduced due to a reduction in battery capacity. The problem of becoming unobtainable is solved. Further, when the PTC is configured as a part of the battery protection circuit, the occupied space of the battery protection circuit is increased and the size reduction is hindered. However, the battery protection circuit of this configuration can configure a battery protection circuit without PTC. .

  In the circuit board 9 on which the battery protection circuit is formed, the main ground pattern 19 connected through the through hole 30 from the lead plate conductor pattern 16a to which one of the pair of lead plates 10 and 10 is connected, and the other lead plate The sub-ground pattern 18 connected through the through hole 30 from the lead plate conductor pattern 16b to which 10 is connected is not directly connected as shown in FIG. With this circuit pattern configuration, it is possible to avoid the formation of a closed circuit in which the pair of lead plates 10 having the base 10b joined to the battery can 31 are connected by the conductor pattern on the circuit board 9. The formation of the closed circuit is easily affected by noise or the like from the applied device, but malfunction due to noise or the like can be prevented by the configuration in which the closed circuit is not formed.

  As shown in FIG. 5A, the positive terminal 4 is formed on the positive terminal conductor pattern 4a formed on the surface side of the circuit board 9, and the negative terminal 5 and the temperature detection terminal are formed on the negative terminal conductor pattern 5a. The temperature detection terminal 6 is joined on the conductor pattern 6a. These terminals are excellent in conductivity, bondability, and corrosion resistance by using a copper-nickel alloy plate material or a clad material of this copper-nickel alloy plate material and stainless steel. Further, without joining plate materials as terminals, each conductor pattern can be used as a terminal by being plated with gold.

  After the circuit board 9 is attached to the secondary battery 1 as described above, the upper insulating holder 13 is disposed on the circuit board 9 and the lower insulating holder 14 is disposed on the bottom surface of the secondary battery 1 as shown in FIG. Then, the entire peripheral surface including the periphery of the upper insulating plate 13 and the lower insulating holder 14 is covered with the insulating label 7, and the secondary battery having the battery protection circuit having the form as shown in FIG. 1 is completed.

  As shown in FIG. 2, the upper insulating holder 13 has a positive terminal window 4c at a position corresponding to the positive terminal 4 provided on the circuit board 9, a negative terminal window 5c at a position corresponding to the negative terminal 5, and a temperature detection terminal. The temperature detection terminal window 6c is opened at a position corresponding to 6, and a step portion 43 for positioning the end side of the insulating label 7 is formed around the temperature detection terminal window 6c. Further, as shown in FIG. 2, the upper insulating holder 13 and the lower insulating holder 14 are formed with lead grooves 41 for accommodating the lead plate 10 on the inner surface side.

Further, as shown in FIGS. 7 and 8, the upper insulating holder 13 and the lower insulating holder 14 are opened at positions corresponding to the lead plates 10, and extended portions 13 a of the upper insulating holder 13 and the lower insulating holder 14, respectively. , 14a is divided into two parts, the width dimensions of the upper insulating holder 13 and the lower insulating holder 14 can be reduced, and the downsizing can be improved. Moreover, if the connection part 13b and 14b which mutually fit is provided in the front-end | tip site | part collided by each extension part 13a and 14a, the connection with the upper insulation holder 13 and the lower insulation holder 14 will be made | formed reliably. Further, if the upper insulating holder 13 and the lower insulating holder 14 are engaged with each other by providing the connecting portions 13b and 14b with a protruding portion 48 and an opening 49, the upper insulating holder 13 and the lower insulating holder 14 are engaged. The connection with 14 becomes more reliable.

  Further, as shown in FIG. 2, when the covering portion 44 covering the upper and lower portions of the long side surface of the secondary battery 1 is formed on the upper insulating holder 13 and the lower insulating holder 14, the fitting to the secondary battery 1 is ensured. Thus, the insulating label 7 can be easily wound. The formation of the covering portion 44 can also be provided in the configuration shown in FIGS. 7 and 8, and does not cover the entire side surface of the secondary battery 1, so that there is room for expansion in the battery can 31 and expansion occurs. In this case, the change in the overall thickness is suppressed. In the secondary battery 1, gas is generated due to repeated charging and discharging or being left at a high temperature in a fully charged state, and the central portion of the mechanically weak battery can 31 tends to swell, but the swelling is within the thickness of the covering portion 44. Therefore, the influence of the thickness change of the secondary battery 1 can be avoided.

  After the upper insulating holder 13 and the lower insulating holder 14 are attached as described above, the insulating label 7 is attached to the lower peripheral side surface from the step portion 43 of the upper insulating holder 13. The insulating label 7 is formed by applying a pressure-sensitive adhesive to a heat-shrinkable sheet, and adheres to each component member and simultaneously covers and integrates each component member by heat shrinkage. Since the surface of the insulating label 7 can be printed on the design, it can be made into an exterior body having a beautiful appearance, and can display instructions for use, warnings, and the like.

  As shown in FIG. 1, the secondary battery having the battery protection circuit configured as described above has a battery protection circuit built in just by slightly extending the height of the secondary battery 1. When set in a device, the battery itself has a battery protection function and becomes a highly reliable battery power source. Moreover, since the positive electrode terminal 4, the negative electrode terminal 5, and the temperature detection terminal 6 arrange | positioned on the upper surface are arrange | positioned asymmetrically, the reverse loading to an apparatus can be prevented.

  The flat secondary battery 1 is mainly used for a battery power source of a small portable electronic device, and an increase in thickness impairs the advantage of the flat battery, but in this configuration, the thickness of the secondary battery 1 is reduced. A battery protection circuit can be provided without increasing the battery, and a secondary battery with a battery protection circuit that is reduced in size and weight rather than in the form of a battery pack is configured, thereby reducing the size and weight of small portable electronic devices. It will contribute to.

  Moreover, although the secondary battery 1 applied to this embodiment showed the example of the lithium ion secondary battery which used the positive electrode input / output terminal 25 and the battery can 31 as the negative electrode input / output terminal in the sealing part, the negative electrode was shown in the sealing part side. A secondary battery having a positive electrode set on the battery can side, that is, a rectangular lithium ion secondary battery obtained by laser sealing with a sealing plate made of aluminum or aluminum alloy using a battery can made of aluminum or aluminum alloy. It goes without saying that even a secondary battery can be similarly implemented by changing the connection.

  A battery pack that integrates a battery protection circuit that protects secondary batteries from overcharge, overdischarge, overcurrent, etc. in a pack case, and is used as a drive power source for portable devices such as mobile phones and digital still cameras. Useful.

External view of secondary battery with battery protection device according to embodiment A perspective view showing the assembly structure by disassembling each component (A) is a plan view showing the configuration of the secondary battery, and (b) is a sectional view. (A) is a plan view on the upper surface side, (b) is a plan view on the lower surface side, and (c) is a cross-sectional view taken along the line AA. (A) is a plan view on the front side, and (b) is a plan view on the back side, showing the configuration of the circuit board. Circuit diagram showing electrical configuration of secondary battery with battery protection circuit (A) is a top view, (b) is a front view, (c) is a left side view, (d) is a right side view, and (e) is a bottom view showing another embodiment of the upper insulating holder. (A) is a top view, (b) is a front view, (c) is a left side view, (d) is a right side view, and (e) is a bottom view showing another embodiment of the lower insulating holder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Secondary battery 4 Positive electrode terminal 5 Negative electrode terminal 6 Temperature detection terminal 7 Insulation label 9 Circuit board 10 Lead board 11 Connection board 12 Spacer 13 Upper insulation holder 14 Lower insulation holder 15, 16a, 16b Conductor pattern 25 Positive electrode input / output terminal (protrusion) Terminal)
31 Battery can 33 Power generation element 37 Positioning part 43 Step part 44 Covering part 51, 52, 53 Connection pad 51a, 51b, 51c, 51d, 52a, 52b, 53a, 53b Joint part 51e, 52c, 53c of conductive pattern and connection pad Connection pad surface

Claims (12)

A positive electrode or a negative electrode is connected to a battery can in which a power generation element is housed in a bottomed cylindrical container, and a protruding terminal provided in the center of a sealing portion that seals the open end of the battery can and insulated from the battery can. A battery protection circuit board formed integrally with a plurality of input / output terminals and a battery protection circuit that protects the secondary battery from overcharging, overdischarging, etc. on the secondary battery that is set respectively, The connection plate joined to the protruding terminal and the lead plate joined to the battery can are connected to the input / output terminals on the battery protection circuit board and joined by soldering or conductive adhesive. A secondary pad formed by covering the circuit board with an upper insulating holder that is connected to the connecting pad and having an opening in the input / output terminal portion and covering the circuit board with an insulating sheet A battery,
The conductor pattern of the protection circuit board and the back surface of the metal connection pad are partially bonded, and the connection plate and the lead plate are bonded to the surface of the connection pad other than the bonded portion. A secondary battery provided with a battery protection circuit. The secondary battery having a battery protection circuit according to claim 1, wherein the protection circuit substrate and the connection pad back surface are joined at four corners of the connection pad back surface. The secondary battery with a battery protection circuit according to claim 1, wherein the protection circuit substrate and the connection pad back surface are joined at edges including four corners of the connection pad back surface. The upper insulating holder further includes a connecting portion formed at the ends of a pair of extending portions extending toward the bottom surface side of the battery can. The bottom surface side of the battery can covers the bottom surface of the battery can. A lower insulating holder having a connecting portion formed at the tip of a pair of extending portions extending toward the sealing portion side of the battery can is arranged to connect the upper insulating holder and the lower insulating holder between the connecting portions. The side peripheral surface of the secondary battery including the side peripheral portions of the upper insulating holder and the lower insulating holder is covered with an insulating sheet, and is configured by any one of claims 1 to 3. Secondary battery with battery protection circuit. The battery protection circuit according to any one of claims 1 to 4, further comprising a spacer that forms a seating surface of the protection circuit board and is spaced apart from the secondary battery. Secondary battery. The secondary battery provided with the battery protection circuit according to claim 1, wherein the protruding terminals of the secondary battery are formed in an oval shape. The battery protection circuit according to any one of claims 1 to 5, wherein an electronic component mounted on the sealing portion side of the protection circuit board is disposed at a position corresponding to a concave portion formed on the sealing portion. Secondary battery provided. The battery protection circuit according to claim 5, wherein the spacer is formed with a positioning portion for the secondary battery and the protection circuit board, and an opening at a position corresponding to the electronic component mounted on the protection circuit board. Secondary battery. The secondary battery provided with the battery protection circuit according to claim 1 or 4, wherein a plurality of input / output terminals provided on the protection circuit board are arranged asymmetrically. The secondary battery provided with the battery protection circuit according to claim 4, wherein the upper insulating holder and the lower insulating holder are connected by overlapping and / or engaging each connecting portion. The secondary battery provided with the battery protection circuit according to any one of claims 1 to 9, wherein the protection circuit board is formed to be equal to or smaller than a cross-sectional size of the secondary battery. The battery protection circuit includes a main control circuit that detects a state such as overcharge and overdischarge and shuts down the charge / discharge circuit, and a sub-control circuit that shuts down the charge / discharge circuit when the main control circuit is abnormal. The secondary battery provided with the battery protection circuit according to claim 1, wherein a heavy protection circuit is formed, and a ground portion of each of the main and sub control circuits is separated.