JP3966751B2 - Battery pack with current interrupting element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is connected to a battery in series, an overcurrent flows through the battery, or a current interrupting element that protects the battery by interrupting the current when the battery temperature rises to an abnormal temperature. The present invention relates to a built-in battery pack.
[0002]
[Prior art]
Current interruption elements such as breakers and PTC elements are used to protect the battery from overcurrent and abnormal temperature rise. These current interrupting elements are connected in series with the battery. The breaker has a built-in bimetal that deforms when heated by an electric current. The bimetal moves the movable contact of the breaker. This bimetal deforms when an overcurrent flows, and separates the movable contact from the fixed contact. In this state, the breaker cuts off the current. The PTC element has a built-in PTC whose electrical resistance increases when the temperature becomes higher than the set temperature. The PTC element is built in the case of the battery pack close to the battery. In this battery pack, when the PTC element is heated by the battery and rises to a set temperature, the electrical resistance of the PTC element increases remarkably and substantially cuts off the current flowing through the battery.
[0003]
[Problems to be solved by the invention]
A conventional battery pack incorporates these current interrupting elements in a case and connects them in series with the battery. The battery pack with this structure can be used safely with a current interrupt device. However, if the current interrupt device cannot be operated normally, the reliability of the battery pack is significantly reduced. It is difficult for the conventional current interruption element to always operate normally depending on the state of being incorporated in the battery pack. For example, a battery pack manufactured by insert molding a part or the whole of a battery into a resin molding part constituting the battery case is not assembled in a case in which the battery pack is molded in advance. There is a drawback that it is difficult to operate the blocking element normally. This is because, when the conventional current interrupting element is insert-molded in the resin molding part and fixed in an embedded state, the resin for molding the resin molding part may enter the case of the current interrupting element. The resin that enters the breaker case may interfere with the movement of the movable contact and may not operate normally. The breaker in which the invading resin forcibly presses the movable contact against the fixed contact cannot cut off the current, and the breaker in which the invading resin presses the moving contact in the direction away from the fixed contact cannot energize. In addition, the resin that has entered the case of the PTC element has a drawback that it cannot be normally energized as the PTC is overheated and tripped to greatly change the electrical resistance of the PTC. The current interrupting element that does not operate normally when the resin enters the case does not operate normally when the battery pack is completed. For this reason, it is necessary to inspect all the manufactured battery packs, and it takes time to inspect, and if defective products are generated in this process, the yield of the battery pack is deteriorated. Further, even if the battery operates normally when inspected, the invading resin may not operate the battery pack normally during use. This not only reduces the yield of battery packs that are mass-produced, but also has the negative effect of reducing reliability. Furthermore, when molding the resin molding part that constitutes the case, it is necessary to set the molding pressure and the like low, which also restricts the manufacturing process.
[0004]
The applicant of the present application has developed a current interrupting device in which the case is molded with a liquid crystal polymer for the purpose of eliminating this problem. This current interrupting element is manufactured by forming a case with two parts including a main body case and a lid case, and ultrasonically welding the lid case to the opening edge of the main body case. The current interrupting device having this structure can improve the reliability because the inside is sealed. Furthermore, in order to make the case a tougher structure, it is reinforced by filling with glass fiber.
[0005]
The current interrupting device having this structure has an advantage that the case can be sealed and the reliability can be improved. However, the glass fibers filled in the liquid crystal polymer for reinforcement may make ultrasonic welding difficult. For example, if glass fibers are exposed on the welding surface between the opening edge of the main body case and the lid case, this prevents complete adhesion between the main body case and the lid case, thereby forming a gap. When this current interrupting element is inserted into the resin molding part, the molten resin penetrates the gap and enters the case. The molten resin that has entered the case causes failure. This is because this resin prevents the normal movement of the contact. If the glass fiber filling amount is reduced in order to avoid this adverse effect, the strength of the main body case and the lid case decreases. The current interrupting element having a reduced case strength cannot withstand the pressure when it is inserted into the resin molded portion. Even if a low temperature molding resin such as a polyamide resin is used for the resin molding portion, the pressure is about 30 atm and the temperature is about 230 ° C. during molding, and a considerably high temperature and high pressure environment is obtained. For this reason, a current interrupting device that cannot withstand this harsh environment will not operate normally due to deformation of the case. By the way, if PTC is used as a current interrupting element, it may trip at the molding temperature, and if a fuse is used, it will be blown by heat.
[0006]
In order to prevent this adverse effect, the applicant of the present application has provided a resin intrusion prevention portion for preventing intrusion of molten resin in the resin molding portion, and a current blocking element is provided in the resin intrusion prevention portion to mold the core pack with resin. We have developed a battery pack that is manufactured by inserting it into the part (Japanese Patent Application 2001-329013). This battery pack is manufactured by inserting a battery core pack into the resin molded portion so that the current interrupting element is not embedded in the resin molded portion. Since the battery pack having this structure is provided with a resin intrusion prevention portion when the resin molding portion is molded, it cannot be easily manufactured and has a drawback of increasing the manufacturing cost. In addition, when the molten heated resin enters the resin intrusion prevention portion in the manufacturing process, there is a disadvantage that the current interrupting element is heated and fails.
[0007]
It was developed for the purpose of solving such drawbacks of the present invention, and an important object of the present invention is that it can be inserted and inserted in a resin molded part to operate reliably, and the reliability and safety are remarkably improved. An object of the present invention is to provide a current interrupting device that can be improved and a battery pack incorporating the current interrupting device.
Furthermore, another important object of the present invention is to provide a current interrupting device that can greatly reduce the failure rate in the manufacturing process, particularly when inserting into a resin molded part, greatly improve the reliability, and can be mass-produced at low cost. Another object of the present invention is to provide a battery pack incorporating this current interrupting element.
Furthermore, another important object of the present invention is to provide a current interrupt device capable of efficiently mass-producing high quality products with less restrictions on the manufacturing process and a battery pack incorporating the current interrupt device. is there.
[0008]
[Means for Solving the Problems]
The battery pack according to claim 1 of the present invention is provided with a resin molding portion 1 in which a core pack 10 of the battery is insert-molded. The resin molding portion 1 is connected in series with the battery 2 and is connected to the battery in an abnormal state. The current interrupting element 6 that interrupts the current flowing through 2 is inserted,
Further, the current interrupting element 6 includes a case 61 formed of plastic, a pair of output terminals 62 fixed to the case 61, and electrically connected to the output terminal 62 and incorporated in the case 61. A current interrupting device comprising a current interrupting unit 63 for interrupting the current by releasing the contact 64 when the temperature is higher than a set temperature or when an overcurrent flows;
The case 61 is composed of a polyamide resin main body case 61A and a lid case 61B that are not filled with a filler, and the main body case 61A has a storage space 65 having an opening for incorporating the current interrupting portion 63, and this storage space. 65 openings are closed with a lid case 61B,
Further, in the step of molding the main body case 61A made of polyamide resin, the pair of output terminals 62 are insert-molded and fixed, and the main body case 61A is formed of the polyamide resin on the entire periphery of the opening,
A lid case 61B made of polyamide resin is ultrasonically welded and adhered to the entire circumference of the opening of the main body case 61A.
When the temperature of the current interrupting element 6 becomes higher than the set temperature or when an overcurrent flows, the contact 64 is released to interrupt the current flowing through the battery 2.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. However, the embodiment shown below exemplifies the current interruption element 6 and the battery pack for embodying the technical idea of the present invention, and the present invention uses the current interruption element 6 and the battery pack as follows. Not specified.
[0011]
Further, in this specification, in order to facilitate understanding of the scope of claims, the numbers corresponding to the members shown in the examples are referred to as “the scope of claims” and “the means for solving the problems”. It is added to the member shown by. However, the members shown in the claims are not limited to the members in the embodiments.
[0012]
The battery pack of FIG. 1 has a resin molded part 1 adhered and fixed to the battery end face. As shown in FIG. 2, the battery pack of the figure has the resin molded part 1 fixed to the electrode end face with the convex electrode 2B. However, the battery pack of the present invention has a battery end face with the convex electrode (not shown). The resin molding part 1 can also be fixed to the battery end surface on the opposite side. Further, although not shown in the drawings, the battery pack of the present invention can also fix the resin molded portion 1 on both narrow side surfaces of the thin battery. The above battery pack is manufactured by temporarily fixing the core pack 10 of the battery 2 in a molding chamber of a mold, injecting molten resin into the molding chamber, and inserting the core pack 10 into the resin molding portion 1. The core pack 10 is obtained by connecting a circuit board 5 and a current interrupting element 6, which is a protection element for the battery 2, to the battery 2. The core pack 10 is shown in the exploded perspective view of FIG. The core pack 10 shown in this figure connects the circuit board 5 and the current interrupting element 6 to the battery 2. The circuit board 5 is connected to the battery 2 via the lead plate 7 and the current interrupting element 6.
[0013]
In the core pack 10, as shown in FIGS. 3 and 4, the holder 4 can be disposed between the circuit board 5 and the battery 2. The holder 4 is manufactured by molding a plastic that is harder than the resin molding portion 1. The holder 4 is formed in a shape to which the circuit board 5 is fitted and disposed at a fixed position, and further, a position fitting part 14 for positioning the battery pack is provided, and the position fitting part 14 is set to the outside. Inserted into the resin molded part 1 as shown. The battery pack having this structure can be provided with the position fitting portion 14 by the hard plastic holder 4. For this reason, the battery pack can be accurately positioned and mounted on the electric device with the position fitting part 14 having a firm structure. The position fixing / inserting portion 14 shown in the figure is a concave portion, and an insertion convex portion provided in an electric device is inserted here to mount the battery pack in a posture determined at a fixed position. The position fitting part can also be a convex part. The position fixing fitting part of a convex part is inserted in the recessed part provided in the electric equipment. The core pack 10 with the holder 4 has a feature that the circuit board 5 can be connected to a fixed position of the battery 2 and temporarily fixed to the mold.
[0014]
The battery pack in which the circuit board 5 of the core pack 10 is inserted into the resin molding part 1 can fix the circuit board 5 at an accurate position by the resin molding part 1. For this reason, the circuit board 5 can be fixed at an accurate position without necessarily using a holder. Further, the core pack 10 without the holder has an advantage over the core pack 10 with the holder 4. This is because, since the circuit board 5 is connected to the battery 2 by the lead plate 7, the relative position between the battery 2 and the circuit board 5 can be slightly adjusted and temporarily fixed in the molding chamber of the mold. The core pack 10 having this structure can be made into a battery pack with less dimensional error by correcting the dimensional error of the battery 2 and molding the resin molding portion 1. The battery 2 can have a dimensional error in length in the manufacturing process. The dimensional error in the length direction of the battery 2 can be absorbed by the distance between the circuit board 5 and the battery 2. For example, a battery pack incorporating a long battery brings the circuit board close to the battery, and a battery pack containing a short battery fixes the circuit board away from the battery. In this way, the overall size of the battery pack can be set to a prescribed size. The distance between the circuit board 5 and the battery 2 is absorbed by deforming the lead plate 7 connecting the circuit board 5 to the battery 2. The mold has a molding chamber that temporarily holds the battery 2 and the circuit board 5 in an accurate position. The core pack 10 is temporarily fixed in the molding chamber while the lead plate 7 is somewhat compressed, and the circuit board 5 and the battery 2 are set in place. In this state, molten resin is injected into the molding chamber to fix the circuit board 5 at an accurate position.
[0015]
The battery 2 is a rechargeable secondary battery such as a lithium ion battery, a nickel-hydrogen battery, or a nickel-cadmium battery. The battery 2 in the figure is a thin battery, and has a shape in which both sides of the outer can 2A are curved surfaces and the corners of the four corners of the outer can 2A are chamfered. When a lithium ion battery is used for a thin battery, there is a feature that the charge capacity with respect to the capacity of the whole pack battery can be increased. In the battery 2, a safety valve 16 is provided on a sealing plate 2C located on an electrode end face on which the convex electrode 2B is provided. The battery 2 in FIGS. 2 and 4 is provided with a convex electrode 2B at the center of the sealing plate 2C and a safety valve 16 at one end. The battery can also incorporate a safety valve in the convex electrode. The safety valve 16 opens when the internal pressure of the battery 2 becomes higher than the set pressure. The opened safety valve 16 discharges internal gas and stops the increase in the internal pressure of the outer can 2A.
[0016]
The circuit board 5 is mounted with an electronic component 9 that realizes a protection circuit for the battery 2. In the battery pack shown in this figure, the protection circuit is mounted on the circuit board 5. However, the protection circuit can be inserted into the resin molding part 1 in the same manner as the current interrupting element 6 with a small IC. In this battery pack, the circuit board 5 can be omitted. Further, the battery pack of FIGS. 2 and 4 has a metal plate output terminal 3 fixed to a circuit board 5. The output terminal 3 is exposed to the outside from the electrode window 12 provided in the resin molding part 1. Further, the circuit board 5 shown in the figure also has a test point terminal 17 which is a metal plate fixed to the surface. The test point terminal 17 is a terminal for testing whether or not the manufactured battery pack operates normally. The test point terminal 17 is also exposed to the outside from the terminal window 13 provided in the resin molding part 1. Since the test point terminal 17 is not used in a normal use state, the battery pack is manufactured and tested for normal operation, and then a seal 18 is applied to close the test point terminal 17.
[0017]
The current interrupting element 6 shown in the exploded perspective view of FIG. 5 and the cross-sectional view of FIG. 6 is connected to the case 61, a pair of output terminals 62 fixed to the case 61, and the output terminals 62, A current interrupting unit 63 having a contact 64 that interrupts the current when the temperature is higher than a set temperature or an overcurrent flows is provided in the case 61.
[0018]
The case 61 includes a main body case 61A and a lid case 61B in which a polyamide resin is molded. The reason why both the main body case 61A and the lid case 61B are molded with polyamide resin is to prevent deformation due to heat and pressure when the current interrupting element 6 is inserted into the resin molding portion 1. When the molded resin part 1 of the battery pack is molded with a polyamide resin which is a low-temperature molding resin or a polyamide resin to which an epoxy resin is added, the molding pressure is about 30 atm and the temperature is about 230 ° C., which is a high temperature and high pressure . The plastic that molds the case 61 of the current interrupting element 6 is a polyamide resin that does not deform with temperature and pressure when molding the resin molding portion 1.
[0020]
The main body case 61A has a storage space 65 having an opening for incorporating the current interrupting portion 63, and the opening of the storage space 65 is closed by a lid case 61B. The illustrated main body case 61 </ b> A has a peripheral wall 66 around the storage space 65. The peripheral wall 66 is provided with a recess 67 for connecting the lid case 61B to a fixed position. The lid case 61B is provided with a convex portion (not shown) that can be fitted into the concave portion 67 so as to protrude from the lower surface. The case 61 having this structure can connect the lid case 61B to the main body case 61A at an accurate position.
[0021]
The body case 61A is a step of molding plastic, and the first output terminal 62A and the second output terminal 62B, which are a pair of output terminals 62, are insert-molded and fixed. The output terminal 62 penetrates the bottom of the main body case 61 </ b> A and protrudes outside from the storage space 65 so as not to appear on the welding surface 66 </ b> A of the peripheral wall 66 provided around the storage space 65. The first output terminal 62A is inserted into the main body case 61A and extended to the bottom surface to reinforce the bottom surface of the main body case 61A. In the main body case 61A, the bottom of the storage space 65 is thinned. The bottom made of thin polyamide resin is easily deformed by heat and pressure when it is inserted into the resin molding part 1. In particular, since the current interrupting element 6 inserted into the resin molded portion 1 of the battery pack needs to be extremely small, the bottom of the storage space 65 is extremely thin. For example, a small current interrupting device having an overall thickness of 1.1 mm is extremely thin with the bottom thickness of the storage space being about 1/3 of the entire thickness. The current interrupting element 6 shown in the figure is configured so that the first output terminal 62A, which is a metal plate, is exposed on the bottom surface in order to reinforce the thin bottom and prevent deformation when inserted into the resin molding portion 1. Inserted and fixed. Further, the first output terminal 62 </ b> A has a thin bottom that is sized to cover almost the entire bottom surface of the resin molded portion 1.
[0022]
The lid case 61B made of polyamide resin is also reinforced by inserting a metal plate 68 therein. The metal plate 68 is also provided so as to close the opening of the storage space 65 provided in the main body case 61A. The illustrated metal plate 68 covers almost the entire opening of the storage space 65. Further, the metal plate 68 is inserted so that one end thereof is embedded in the lid case 61B, and is firmly fixed to the lid case 61B. Thus, the current interrupting element 6 that inserts the metal plate 68 into the main body case 61A and the lid case 61B and reinforces the polyamide resin above and below the storage space 65 is inserted into the resin molding portion 1 and molded. It has the feature that it is not deformed by pressure and heat.
[0023]
The second output terminal 62B fixed to the main body case 61A is exposed to the recess 67 of the main body case 61A and is electrically connected to the movable arm 69 disposed therein. The first output terminal 62A and the second output terminal 62B are inserted and fixed to the main body case 61A so as not to contact each other. The main body case 61A has a structure in which the output terminal 62 is not exposed to the welding surface 66A of the peripheral wall 66, and the entire periphery of the opening, in other words, the entire periphery of the welding surface 66A of the peripheral wall 66 is formed of polyamide resin. The illustrated main body case 61A has a flat opening and is closed by a plate-like lid case 61B. The main body case 61A is in close contact with the entire circumference of the opening by ultrasonically welding a lid case 61B made of polyamide resin. In the case 61 having this structure, the lid case 61B is ultrasonically welded to the welding surface 66A of the peripheral wall 66 provided in the main body case 61A, and the lid case 61B is welded along the entire circumference of the opening of the storage space 65. The storage space 65 is sealed. The lid case 61B is welded to the entire circumference of the opening of the main body case 61A, so that the storage space 65 has a completely sealed structure. Therefore, when the current interrupting element 6 is inserted into the resin molded part 1 of the battery pack, the heated and melted plastic does not enter the case 61.
[0024]
The current interrupting element 6 shown in the figure is a breaker, and the current interrupting part 63 has a contact 64 that interrupts the current. The contact 64 is an end of a movable arm 69 electrically connected to a fixed contact 64A provided on the first output terminal 62A which is one output terminal 62 and a second output terminal 62B which is the other output terminal 62. And a movable contact 64B. The movable arm 69 is a conductive metal plate that can be elastically deformed. In the illustrated movable arm 69, a movable contact 64B is provided at one end, and the other end is electrically connected to the second output terminal 62B. A portion that is electrically connected to the output terminal 62 is branched into a T shape and is fitted into a recess 67 provided in the main body case 61A. Further, the T-shaped branch portion 69A is electrically connected so as not to be contacted by being pressed against the second output terminal 62B by the lid case 61B welded to the main body case 61A.
[0025]
The movable contact 64 </ b> B is pressed by the fixed contact 64 </ b> A by the elastic force of the movable arm 69 that is elastically deformed, so that the current interrupting element 6 is energized. When the movable contact 64B moves away from the fixed contact 64A, the current interrupt device 6 is in a state of interrupting current. In the illustrated current interrupting element 6, a disk 70 that deforms the movable arm 69 by being deformed by heat is disposed between the fixed contact 64 </ b> A and the movable contact 64 </ b> B. The disk 70 is a thermal expansion difference laminated metal plate such as bimetal or trimetal. In this breaker, when a current smaller than the set current flows or when the temperature of the battery is lower than the set temperature, the movable arm 69 elastically presses the movable contact 64B against the fixed contact 64A to be in an energized state. When an excessive current larger than the set current flows or becomes higher than the set temperature, the disk 70 is thermally deformed, the deformed disk 70 deforms the movable arm 69, and the movable contact 64B is separated from the fixed contact 64A. Shut off.
[0026]
In the battery pack, the core pack 10 is temporarily fixed in the molding chamber to mold the resin molding portion 1. The synthetic resin for molding the resin molding portion 1 is a low temperature molding resin. The low temperature molding resin is a polyamide resin or a polyurethane resin. An epoxy resin can be added to the polyamide resin. The polyamide resin to which the epoxy resin is added can increase the adhesive strength as compared with the polyamide resin alone. Polyamide resins and polyurethane resins have a low softening temperature and a low viscosity at the time of melting, so that they can be molded at a lower temperature and a lower pressure than other thermoplastic synthetic resins. Another feature is that it can be quickly removed from the mold chamber. The resin molded part 1 molded at a low temperature and a low pressure has features that it can shorten the time required for molding and reduce adverse effects on electronic components and the like due to heat and injection pressure during resin molding.
[0027]
However, the battery pack of the present invention does not specify the resin for forming the resin molding portion 1 as a polyamide resin and a polyurethane resin. Any thermoplastic resin that is not a polyamide resin or a polyurethane resin and does not adversely affect the current interrupting element 6 and the electronic component 9 of the circuit board 5 due to heat and pressure can be used. A thermoplastic resin such as polyethylene, acrylic, or polypropylene resin can be used as long as the heat resistance of an electronic component that realizes a protection circuit or the like inserted into the resin molded portion 1 can be improved.
[0028]
The core pack 10 that connects the circuit board 5 and the current interrupting element 6 to the battery 2 is temporarily secured in the molding chamber of the mold, and the resin molding part 1 is molded so that the current interrupting element 6 is inserted. In the battery pack shown in the cross-sectional views of FIGS. 7 and 8, molten resin is injected between the circuit board 5 and the battery end face, the resin molding portion 1 is provided here, and the current interrupting element 6 and the circuit board 5 are connected to the battery. 2 is fixed. Further, in the battery pack shown in the figure, the resin molded portion 1 is also formed on the upper surface of the circuit board 5 to firmly connect the circuit board 5 to the battery end face. The battery pack shown in FIG. 7 has a through hole 15 in the circuit board 5, a molten resin is injected into the through hole 15, and the resin molding portions 1 on both the upper and lower sides of the circuit board 5 are connected by the resin in the through hole 15. Yes. This structure can be connected to the circuit board 5 so as not to peel the resin molded portion 1 more firmly. In particular, a battery pack in which a plurality of through-holes 15 are provided in the circuit board 5 and the resin molded parts 1 are connected to both the upper and lower surfaces of the battery pack so that the thin resin molded part 1 molded on the upper surface of the circuit board 5 is not peeled off firmly. It can be adhered to the substrate 5.
[0029]
Furthermore, the resin molding part 1 has the wrap thin part 11 extended from the battery end surface to the outer peripheral surface of the battery 2, as shown in FIG. 7 and FIG. The thin wrap portion 11 is formed integrally with the resin molding portion 1 and is adhered to the outer peripheral surface of the battery 2 when the resin molding portion 1 is molded. The molten resin injected into the molding chamber of the mold is injected from the battery end surface to the portion where the wrap thin portion 11 is formed, and the wrap thin portion 11 is formed integrally with the resin molding portion 1. The wrap thin portion 11 is preferably provided on the entire circumference of the outer peripheral surface of the battery. The resin molded portion 1 is connected to the battery 2 so as not to be peeled off most at the wrap thin portion 11 provided on the entire outer peripheral surface. However, the wrap thin part 11 can also be provided only on the outer peripheral surface of the wide surface of the thin battery.
[0030]
When the wrap thin part 11 is thick, the outer shape of the battery pack is enlarged, and when the wrap thin part 11 is thin, sufficient strength cannot be obtained. For this reason, the wall thickness of the wrap thin part 11 is preferably 0.1 to 0.3 mm, more preferably 0.1 to 0.2 mm. The thick wrap thin portion 11 does not substantially increase the thickness of the entire battery pack incorporating the thin battery. This is because the amount of swelling is absorbed by the thin battery when it is used. A thin battery has the property that when the internal pressure rises, the central portion is somewhat swollen and thick. The above-described thick wrap thin portion 11 is smaller than the “swell amount” of the thin battery. Furthermore, although the wrap thin part 11 is provided extending from the battery end face to the outer peripheral surface, this part does not swell. For this reason, when the center of the thin battery expands due to an increase in internal pressure, the thickness of the battery pack in the portion where the wrap thin portion 11 is provided is thinner than the expanded central portion. For this reason, providing the wrap thin portion 11 does not substantially increase the thickness of the entire battery pack incorporating the thin battery.
[0031]
The width (W1) of the wrap thin portion 11 can be increased to increase the bonding strength with the battery 2. Even if the wrap thin part 11 is considerably narrowed, the resin molded part 1 can be firmly adhered to the battery end face. In particular, as shown in the figure, the battery pack whose surface is covered with the surface covering sheet 19 can be pressed against the battery surface with the surface covering sheet 19 so as not to peel off. For this reason, the width | variety (W1) of the wrap thin part 11 can be narrowed with 0.1-2 mm, Preferably 0.2-1 mm, for example, 0.5 mm, and the resin molding part 1 can be connected to the battery 2 firmly. The narrow wrap thin portion 11 can be molded into a prescribed shape by reliably injecting a molten synthetic resin.
[0032]
The surface covering sheet 19 is a heat shrinkable tube that can be shrunk by heating. This surface covering sheet 19 is brought into close contact with the surfaces of the resin molded part 1 and the wrap thin part 11 and firmly connects the resin molded part 1 to the battery 2. Further, the battery pack covered with the surface covering sheet 19 does not intrude between the wrap thin portion 11 and the battery 2 and this prevents the wrap thin portion 11 from being peeled off. . However, the surface covering sheet may be a label or an adhesive tape. A surface covering sheet, which is a label or an adhesive tape, is affixed to the surface of the resin molded portion and the wrap thin wall portion or the surface of the battery to firmly connect the resin molded portion to the battery.
[0033]
In the battery pack of FIG. 7 and FIG. 8, a step 20 is provided on the outer periphery of the resin molded portion 1, and the portion that is molded low is covered with the surface covering sheet 19. In the resin molded portion 1, the surface covering sheet 19 does not protrude from the resin molded portion 1, and the surfaces of the resin molded portion 1 and the surface covering sheet 19 can be made substantially flush with each other.
[0034]
Furthermore, the battery pack shown in the figure covers the bottom surface of the battery 2 with a plastic molded body 21 in the figure on the battery end surface opposite to the side where the resin molding portion 1 is molded. The plastic molded body 21 is molded from a plastic that is harder than the resin molded portion 1. The plastic molded body 21 is integrally formed with a bottom portion 22 covering the front surface of the battery end surface and a second wrap thin portion 23 extending from the battery end surface to the outer peripheral surface of the battery 2. The bottom portion 22 is formed thicker than the second wrap thin portion 23, and is provided with a hook recess 24 into which the user inserts a toe when the battery pack is detached from the electrical device. The battery pack can be smoothly removed from the electric device by inserting a nail into the hook recess 24. Moreover, since the part provided with the catching recessed part 24 is shape | molded with hard plastic, this part can be made into a tough structure.
[0035]
The second wrap thin part 23 is formed to have the same thickness as the wrap thin part 11 of the resin molding part 1. However, the width (W2) of the second wrap thin part 23 is wider than the width (W1) of the wrap thin part 11 of the resin molded part 1 and is 1 to 5 mm, preferably 1.5 to 3 mm, for example 2 mm. . This is because it is covered with the surface covering sheet 19 and firmly connected to the battery 2. The plastic molded body 21 is bonded and fixed to the battery 2 and further connected by the surface covering sheet 19.
[0036]
The above battery pack is manufactured as follows.
(1) The circuit board 5 is connected to the battery 2 with the current interrupting element 6 and the lead plate 7, and the current interrupting element 6, the circuit board 5 and the holder 4 are arranged at fixed positions of the battery 2 to manufacture the core pack 10. To do. In the core pack 10 with the holder 4, the holder 4 is disposed between the circuit board 5 and the battery 2. The core pack 10 that connects the plastic molded body 21 to the bottom adheres and fixes the plastic molded body 21.
[0037]
(2) Set the core pack 10 in the molding chamber of the mold. After setting the core pack 10 in the molding chamber, the mold is clamped. The mold clamped is formed with a molding chamber for molding the resin molding part 1. Heated molten resin is injected into the molding chamber to mold the resin molding portion 1. The molten resin is injected from a liquid injection hole opened in the mold. The injected molten resin inserts and fixes the current interrupting element 6 and is injected up to the portion where the wrap thin portion 11 is formed, thereby forming the wrap thin portion 11 integrated with the resin molding portion 1.
(3) After the resin molding part 1 is cured, the mold is opened, and the battery pack in which a part of the core pack 10 is insert-molded in the resin molding part 1 is taken out.
[0038]
(4) After that, the battery pack is put into a cylindrical surface covering sheet 19 that is a heat shrinkable tube, and the heat shrinkable tube is heated to adhere to the surface of the battery pack. The surface covering sheet 19 is closely attached to the step 20 provided in the resin molded part 1 and the plastic molded body 21, and firmly connects the resin molded part 1 and the plastic molded body 21 to the battery 2.
[0039]
(5) Insert a needle electrode into the test point terminal 17 to test whether or not the battery pack operates normally, confirm that it operates normally, and close the terminal window 13 of the test point terminal 17 The seal 18 is adhered to the surface.
[0040]
【The invention's effect】
Battery pack provided a current cut-off device of the present invention is to insert a current cut-off device in an embedded state in the resin molding part can operate reliably, there is a feature that can significantly improve the reliability and safety. The current interrupting element of the present invention fixes a pair of output terminals to a case in which a polyamide resin is molded, and a current interrupting part having a contact for interrupting current by being electrically connected to the output terminal is incorporated in the case This is because the battery pack of the present invention uses this current interrupting element as a current interrupting element inserted into the resin molding part in which the core pack of the battery is insert-molded.
[0041]
The current interruption element used for the battery pack provided with the current interruption element of the present invention is characterized in that the case is formed of a polyamide resin. Thus, the case molded from the polyamide resin can realize superior strength and heat resistance compared to the case molded from the liquid crystal polymer or the like. For this reason, even if the current interruption element used for the battery pack provided with the current interruption element of the present invention is inserted into the resin molded part, the case is deformed by the heat and pressure of the heated molten resin, or the molten resin is the case. It is possible to effectively prevent the current interrupting element from being broken and to prevent failure of the current interrupting element.
[0042]
Furthermore, the current cut-off device for use in a battery pack comprising a current cut-off device of the present invention, the casing, constituted by the main body case and the cover case made of polyamide resin is not filled in charge Hamazai current interrupting the storage space of the main body case The opening is closed with a lid case. Particularly, the main body case is formed by forming the entire circumference of the opening with polyamide resin, and a lid case made of polyamide resin is ultrasonically welded to the entire circumference of the opening. For this reason, it is possible to reliably prevent a gap from being formed in the welded portion by completely adhering the welded portion without causing poor welding as in the case of a liquid crystal polymer case filled with glass fiber and reinforced.
[0043]
Therefore, the battery pack equipped with the current interrupting device of the present invention can greatly reduce the failure rate in the manufacturing process, particularly the failure when inserted into the resin molded part, remarkably improve the reliability and safety, and inexpensively in large quantities. Can be produced. Furthermore, there is a feature that the restriction in the manufacturing process of inserting the current interrupting element into the resin molding part can be reduced, and high-quality products can be efficiently mass-produced.
[Brief description of the drawings]
1 is an exploded perspective view of a battery pack according to one embodiment of the present invention. FIG. 2 is an exploded perspective view of a core pack of the battery pack shown in FIG. 1. FIG. 3 is a battery pack according to another embodiment of the present invention. FIG. 4 is an exploded perspective view of the core pack shown in FIG. 3. FIG. 5 is an exploded perspective view of a current interrupting element according to an embodiment of the present invention. FIG. 7 is a cross-sectional view of a resin molded portion of the battery pack shown in FIG. 1. FIG. 8 is a vertical cross-sectional view of the battery pack shown in FIG.
DESCRIPTION OF SYMBOLS 1 ... Resin molding part 2 ... Battery 2A ... Exterior can 2B ... Convex part electrode 2C ... Sealing board 3 ... Output terminal 4 ... Holder 5 ... Circuit board 6 ... Current interruption element 7 ... Lead board 9 ... Electronic component 10 ... Core pack 11 ... Wrap thin part 12 ... Electrode window 13 ... Terminal window 14 ... Position fitting part 15 ... Through hole 16 ... Safety valve 17 ... Test point terminal 18 ... Seal 19 ... Surface covering sheet 20 ... Step 21 ... Plastic molding 22 ... Bottom 23 ... 2nd wrap thin part 24 ... hook recessed part 61 ... case 61A ... main body case 61B ... lid case 62 ... output terminal 62A ... 1st output terminal 62B ... 2nd output terminal 63 ... current interruption part 64 ... contact 64A ... fixed contact 64B ... movable contact 65 ... storage space 66 ... peripheral wall 66A ... welding surface 67 ... concave 68 ... metal plate 69 ... movable arm 69A ... branch 70 ... disk

Claims (1)

Battery core pack (Ten) Resin molded part with insert molding (1) This resin molded part (1) The battery (2) Connected in series with the battery in case of abnormality (2) Current interrupting element that interrupts the current flowing through (6) Is inserted,
  Furthermore, the current interruption element (6) The case is molding plastic (61) And this case (61) A pair of output terminals fixed to (62) And this output terminal (62) Is electrically connected to the case (61) Built-in to contact when the temperature is higher than the set temperature or overcurrent flows (64) Current interrupting unit that releases current by releasing (63) A current interrupting device comprising:
  Case (61) Is a body case made of polyamide resin that is not filled with filler (61A) And lid case (61B) The body case (61A) Is the current interrupter (63) Storage space with an opening to incorporate (65) Have this storage space (65) The opening of the lid case (61B) Blocked by
  In addition, a body case made of polyamide resin (61A) In the process of forming a pair of output terminals (62) The body case is fixed by insert molding (61A) Is made of polyamide resin around the entire circumference of the opening,
  Body case (61A) A cover case made of polyamide resin on the entire circumference of the opening (61B) Are made by ultrasonic welding
  Current interruption element (6) When the temperature of the battery becomes higher than the set temperature or overcurrent flows, (64) Release the battery (2) A battery pack comprising a current interrupting element configured to interrupt current flowing through the battery.

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