JP4609369B2 - Battery pack and battery pack manufacturing method - Google Patents

Description

The present invention is, for example, a secondary battery such as a Lithium ion battery, other electronic components (collectively except description of the embodiments referred to as "article") relates to a battery pack and a manufacturing how accommodating the is there.

  Conventionally, when two or more plates made of a thermoplastic resin such as polycarbonate are welded using ultrasonic vibration, it is essential that the thickness of the plate on the welding surface is at least 1.0 mm or more. In addition, after storing one or more cylindrical cells of a lithium ion battery inside the battery case, ultrasonic vibration is applied to weld the battery case to produce a lithium ion battery. Since the heat of vibration is applied to the lithium ion battery and it may explode, this ultrasonic welding method has not been used, so far, this type of battery is sealed using an organic solvent to seal the battery case, It was enclosed.

However, the bonding method of encapsulating parts using organic solvents is
1. 1. It takes time to bond and fix in the manufacturing process, and the production efficiency is poor. 2. Since the solvent is used, the solvent protrudes or repels from the adhesive surface of the case, and the solvent adheres to parts other than the adhesive surface of the case, resulting in many appearance defects that contaminate the appearance of the case. 3. It is necessary to manage the solvent regularly in the manufacturing process, and the process management becomes complicated. 4. Because it is an organic solvent, it is necessary to pay attention to the work environment. Since an organic solvent is used, there is a problem that it is not good for the global environment.

  The present invention is intended to solve such problems. Even in the case of a welded surface with a thin plate thickness, ultrasonic vibrations can be used without damaging an article housed therein. It is an object of the present invention to obtain a thin-walled case that can be easily welded and an ultrasonic welding method thereof.

In order to solve the above-described problem, the battery pack of the present invention includes a first case half in which a plurality of energy director portions and slit portions that are welded by ultrasonic waves are alternately arranged on both sides facing each other on the opening surface. A plurality of engagement claws inserted into the slit portion and a plurality of receiving portions for receiving the energy director portion, and a second case half that fits into the first case half, and a battery cell The first and second case halves are fitted in a state in which the first and second case halves are welded by applying ultrasonic vibration to the energy director portion.

In the battery pack manufacturing method of the present invention, the first case half or the slit in which a plurality of energy director portions and slit portions welded by ultrasonic waves are alternately arranged on both sides facing each other on the opening surface A plurality of engaging claws inserted into the part and a plurality of receiving parts for receiving the energy director part, and a step of accommodating the battery cell in a second case half that fits into the first case half; In the state in which the battery cell is housed in the first or second case half, the step of fitting the first and second case half, and in the fitted first and second case half, A step of welding the first and second case halves by applying ultrasonic vibration to the director portion.

Therefore, according to the present invention, it is possible to instantaneously weld the thin case and enclose the article without damaging the article housed therein and the thin case itself. Effect.
1. 1. Since the case half can be welded instantly, the working time can be greatly reduced. Therefore, it is optimal for mass production facilities. Since no organic solvent is used, the environment can be kept good. 4. Since no organic solvent is used, process management is easy. 5. Do not damage the built-in items. The appearance of the finished product is difficult to cause.

Hereinafter, a battery pack and a manufacturing method thereof according to the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a thin case used in the battery pack of the present invention, FIG. 2 is a partially enlarged cross-sectional view of the thin case shown in FIG. FIG. 4 is a partially enlarged cross-sectional view of the thin case shown on line B-B, FIG. 4 shows an ultrasonic welding horn used in the ultrasonic welding method of the present invention, and FIG. B is a side view of the long side, FIG. C is a side view of the short side, and FIG. 5 is a state before the cylindrical cell of the battery is accommodated by inverting the thin case shown in FIG. FIG. 6 is a perspective view of the thin case in the state, and FIG. 6 is a perspective view of the thin case in the cylindrical cell storage state shown in FIG. 5 and the ultrasonic welding horn shown in FIG. 7 is a cross-sectional side view, and FIG. 7 is a thin case intermediate body or lid side case half body shown in FIG. FIG. 7A is a partially enlarged perspective view of the formed receptacle, FIG. B is a perspective view of a portion of FIG. A further enlarged, and FIG. FIG. 8 is a partially enlarged perspective view showing still another structure of the receiver formed on the intermediate body or the lid-side case half of the thin case shown in FIG.

First, the structure of the thin case used in the battery pack of the present invention will be described with reference to FIGS. 1 to 3.
Reference numeral 100 denotes the thin case of the present invention. The thin case 100 has a bottomed case half 110 having a relatively shallow depth and a lid side case half 120 having a relatively deep depth, or depending on the bulkiness of articles to be stored in these cases. And an intermediate body 130 for increasing the volume of the case.
For example, in the case of a case in which the lithium ion battery Ba is enclosed, the thickness of the thin case 100 is usually about 1.0 mm even in a thick portion.

  In the present specification, the “bottom” of the “bottom-side case half” sometimes means “lid”, and the “lid” of the “lid-side case half” is sometimes “ It may mean “bottom”. It should be noted that these “bottom” and “lid” are names given for convenience for easy understanding.

  When this thin case 100 is used, for example, for a battery pack case in which a lithium ion battery Ba is enclosed, for example, two cylindrical cell lithium ion batteries Ba are accommodated on the lid side case half 120 side. On the other hand, the bottomed case half 110 accommodates a bulky electronic component such as an electronic circuit for displaying the charge state of the built-in rechargeable ion battery Ba.

When the volume of the article to be stored in the bottomed case half 110 is bulky, as shown in FIG. 1, the relatively shallow bottomed case half 110 and the lid side case half 120 are interposed. By inserting the intermediate body 130, the entire volume of the thin case 100 can be increased.
Therefore, in the case where, for example, the lithium ion battery Ba is sealed in the thin case 100 in which the intermediate body 130 is combined, for example, two cylindrical cells are disposed on the lid side case half 120 side where the depth is shallow. The lithium ion battery Ba is housed, and the volume of the electronic circuit that displays the state of charge of the lithium ion battery Ba built in the bottomed case half 110B side and the intermediate body 130, one of which is shallow, is bulky. It is good to divide and store electronic components.

Next, the structures of the bottomed case half body 110, the lid side case half body 120, and the intermediate body 130 will be described.
The bottomed case half 110 is composed of a rectangular bottom plate 111, a long side plate 112 and a short side plate 113 formed perpendicular to the plane of the bottom plate 111 from each side of the bottom plate 111, and At least a 2 mm width portion of the outer peripheral edge portion H of the outer surface of the bottom plate 111 is formed into a flat surface (hatched portion in FIG. 5). In the case of the battery case shown in FIG. 5, in order to attach the battery to an electronic device such as a video, a plurality of females to which engagement claws or the like formed on the battery attachment portion of the electronic device can be fitted. A mold engaging hole 114 is formed from the outer peripheral edge portion H to the long side plate 112 or the short side plate 113.

Further, an end surface which becomes a part of the welding surface of the long side plate 112 and the short side plate 113 has an energy director 115 as shown in FIG. 2 and a plurality of slits 116 as shown in FIG. Is formed.
The energy director 115 has a knife-edge-like structure in which a vertical surface 1151 slightly retracted from the outer surface of the long side plate 112 and the short side plate 113 is formed, as shown in a part of FIG. Yes. The angle of the knife edge is set at an angle of 45 degrees so that the melted resin can easily enter the gap G described later.
The slits 116 are formed at a plurality of locations where a part of the energy director 115 does not exist.

Next, the structure of the lid-side case half 120 will be described. The lid-side case half 120 serves as a receiving side of the bottomed case half 110, and a receiving portion 121 for receiving the energy director 115 is formed at the peripheral edge of the opening. The receiver 121 has a lower inner peripheral surface side 1211 and a higher outer peripheral surface side 1212, and when the energy director 115 is received, the vertical surface 1151 (outer surface) of the energy director 115 and the outer peripheral surface of the receiver 121. A slight gap G is formed between the inner surface of the side 1212 and the cross section is formed in a stepped structure.
Further, as shown in FIG. 3, the slit 116 formed on the opening end surface of the bottomed case half 110 is formed on the end surface that becomes a part of the welding surface of the opening of the lid case half 120. A plurality of engagement claws 122 having a size that can be inserted into each slit 116 is formed corresponding to the number and position.

Next, the structure of the intermediate 130 will be described. The structure of the opening end face into which the lid-side case half 120 of the intermediate body 130 is fitted and welded is the structure of the opening end face of the bottomed case half 110 as shown in FIGS. And an energy director 135 (FIG. 2) and a plurality of slits 136 (FIG. 3) are formed.
Further, the structure of the end face on the opening side (the back side of the intermediate body 130 in FIG. 1) into which the bottomed case half body 110 of the intermediate body 130 is fitted and welded is as shown in FIGS. In addition, it is the same as the structure of the opening end surface of the said lid | cover side case half body 120, Comprising: A receptacle and an engaging claw (all are not shown) are formed.

  As shown in FIG. 2, the thickness of the plate of the bottomed case half body 110 is, for example, 1.0 mm, and the thickness of the plate of the lid side case half body 120 is, for example, 0.8 mm.

Next, the structure of an ultrasonic horn used in the ultrasonic welding method of the present invention will be described with reference to FIG.
In this ultrasonic horn 1, a plurality of protrusions 4 having different shapes are formed on the lower end surface 3 (FIG. 4A) of the horn main body 2 and abut against the outer peripheral edge portion H of the bottomed case half 110. These protrusions 4 are formed with a width of, for example, 2 to 3 mm from the outer peripheral edge of the outer peripheral edge H, avoiding the engagement holes 114 formed in the outer peripheral edge H of the bottomed case half 110. Has been. If this width is widened, the applied ultrasonic vibration acts on the battery enclosed in the thin-walled case 100, for example, there is a risk of causing an explosion. Therefore, the width is as much as possible. It is desirable to make it narrow. These protrusions 4 have the same height, and the surfaces formed by connecting the tips of the protrusions 4 are the same plane.

Next, an ultrasonic welding method for welding the thin case 100 containing the lithium ion battery Ba by ultrasonic vibration using the ultrasonic horn 1 will be described with reference to FIGS.
First, as shown in FIG. 5, in the case shown in the figure, two lithium ion batteries Ba are accommodated in the lid-side case half 120 with a predetermined polarity. Then, as shown in FIGS. 2 and 3, the energy director 115 of the bottomed case half 110 is fitted to the receiver 121 of the lid case half 120 in the housed state, and the lid side case half is fitted. The engaging claw 122 of the body 120 is inserted into the slit 116 of the bottomed case half body 110, and both are united.

  Thereafter, as shown in FIG. 6, the thin case 100 in this state is installed and fixed in the recess 11 of the receiving jig 10 with the lid side case half 120 side down, and the bottomed case half The ultrasonic horn 1 is lowered from above the bottom plate 111 of the body 110. In this case, it goes without saying that each protrusion 4 of the ultrasonic horn 1 is adjusted so as to avoid the engagement hole 114 in the outer peripheral edge portion H of the bottom plate 111 and to contact with a width of 2 to 3 mm from the outer peripheral edge. .

  When this setting is completed, next, for example, ultrasonic vibration having an output frequency of 20 Hz and an amplitude of 60 to 70 μm is applied. The applied ultrasonic vibration is conducted from the protrusion 4 of the ultrasonic horn 1 to the energy director 115 and the slit 116 formed in the bottomed case half body 110 and received in the lid side case half 120. Stress is applied to 121 and the like, and frictional heat is generated, and the bottomed case half 110 and the lid side case half 120 are instantaneously welded in a short time such as 0.2 to 0.3 mmsec.

In this case, a part of the energy director 115 is melted and flows into the gap G shown in FIG. 2 and is welded not only to the inner peripheral surface side 1211 of the receiver 121 but also to the inner wall of the outer peripheral surface side 1212.
Further, the projection 4 of the ultrasonic horn 1 is not in contact with the engagement hole 114 formed in the bottom plate 111 of the bottomed case half 110, and the ultrasonic wave is directly below the engagement hole 114. Although no vibration is applied, ultrasonic vibrations circulate from both sides of the respective engagement holes 114 to melt the resin of the case.
Therefore, the bottomed case half body 110 and the lid side case half body 120 are firmly welded, and ultrasonic welding of the thin-walled case 100 that has been impossible until now is possible.

  Further, since the plurality of engaging claws 122 are formed on the opening welding surface of the bottomed case half body 110, both the long side plates 112 of the bottomed case half body 110 are subjected to the pressing force of the ultrasonic horn 1. However, as indicated by the arrow X, the ultrasonic vibration is directly transmitted from the energy director 115 to the receiver 121 in order to prevent it from spreading outward, so that the melting energy does not escape and the welding is performed more firmly. be able to.

  In the case where the intermediate body 130 shown in FIG. 1 is inserted between the bottomed case half body 110 and the lid side case half body 120 for ultrasonic welding, a patent application filed on the same date as the present specification ( If the ultrasonic welding method disclosed in JP-A-10-236439) is adopted, the three parties can be easily welded by ultrasonic waves. That is, ultrasonic vibration is applied to the fitting portion between the bottomed case half body 110 and the intermediate body 130 in the vertical direction from above the bottomed case half body 110, as shown in FIG. In addition, by applying ultrasonic vibration with an ultrasonic horn to the fitting part between the intermediate body 130 and the lid-side case half 120 from the lateral direction or obliquely above the part, the three parts Can be welded.

  As shown in FIG. 2, the welding surface on the inner peripheral surface side 1211 of the receiver 121 on the receiving side such as the lid-side case half 120, that is, the surface of the receiver 121 of the energy director 115 is as shown in FIG. Instead of a mirror surface, for example, a triangular wave surface with an angle of 90 °, a mountain height of 0.25 mm, and a width of 0.5 mm, or a pear finish as shown in FIG. If so, the frictional force due to the ultrasonic vibration is increased, the welding strength is improved by 20% to 30% compared to the case of mirror finish, and both can be welded in a shorter time.

  In the above embodiment, the battery is taken up as an article to be housed in the thin case, but it should be noted that the article to be housed in the thin case of the present invention is not limited to the battery or the electronic component.

It is a perspective view of the case (thin case) used for the battery pack of the present invention. It is a partially expanded sectional view on the AA line of the thin case shown in FIG. It is a partially expanded sectional view on the BB line of the thin case shown in FIG. The ultrasonic welding horn used for the manufacturing method of this invention is shown, The figure A is the front view, The figure B is the side view of the long side, The figure C is the side view of the short side . It is a perspective view of the thin case of the state before inverting the thin case shown in FIG. 1, storing the cylindrical cell of a battery, and enclosing. FIG. 6 is a cross-sectional side view showing the thin-walled case accommodated in the cylindrical cell shown in FIG. 5 and the ultrasonic welding horn shown in FIG. 4 for explaining the ultrasonic welding method of the present invention. The other structure of the receiver formed in the intermediate body of the thin case shown in FIG. 1 or the lid-side case half is shown, FIG. A is a partially enlarged perspective view thereof, and FIG. It is the perspective view which expanded and showed a part of. FIG. 6 is a partially enlarged perspective view showing still another structure of a receiver formed on the intermediate body or the lid-side case half of the thin case shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Ultrasonic horn, 2 ... Horn main body, 3 ... Lower end surface of ultrasonic horn 1, 4 ... Protrusion, 10 ... Receiving jig, 11 ... Recess of receiving jig 10, 100 ... Thin-walled case of the present invention (for package) Case), 110 ... Bottomed case half, 114 ... Engagement hole, 115, 135 ... Energy director, 1151 ... Vertical plane of energy director 115, 116, 136 ... Slit, 120 ... Lid side case half, 121 ... Receiving member 1211 ... Inner peripheral surface side 1211, 1212 of the receiving member 121, 122 receiving outer peripheral surface side, 122 ... Engaging claw, 130 ... Intermediate body, G ... Gap, H ... Outer peripheral edge portion, Ba ... Lithium ion battery

Claims (5)

A first case half in which a plurality of energy director portions and slit portions that are welded by ultrasonic waves are alternately arranged on both sides facing each other on the opening surface;
A plurality of engaging claws inserted into the slit portion and a plurality of receiving portions for receiving the energy director portion, and a second case half that fits into the first case half,
The first and second case halves are fitted in a state in which the battery cell is accommodated, and the first and second case halves are welded by applying ultrasonic vibration to the energy director portion. battery pack. A first case half in which a plurality of energy director portions and slit portions that are welded by ultrasonic waves are alternately arranged on both sides facing each other on the opening surface;
A plurality of engaging claws inserted into the slit portion and a plurality of receiving portions for receiving the energy director portion, and a second case half that fits into the first case half,
The first and second case halves are fitted in a state in which the battery cell is accommodated, and the first and second case halves are welded by applying ultrasonic vibration to the energy director portion. And
The receiving portion, the inner peripheral surface side is low, high outer peripheral surface side, and when receiving the energy director unit, slight between the outer peripheral surface side of the inner surface of the receiving portion and the outer surface of the energy director unit a gap is formed, the battery pack cross-section formed in a stepped structure. A first case half in which a plurality of energy director portions and slit portions that are welded by ultrasonic waves are alternately arranged on both sides facing each other on the opening surface;
A plurality of engaging claws inserted into the slit portion and a plurality of receiving portions for receiving the energy director portion, and a second case half that fits into the first case half,
The first and second case halves are fitted in a state in which the battery cell is accommodated, and the first and second case halves are welded by applying ultrasonic vibration to the energy director portion. And
The slit portion is a battery pack that is large enough to fit the engaging claw . A first case half in which a plurality of energy director portions and slit portions welded by ultrasonic waves are alternately arranged on both sides facing each other on the open surface, or a plurality of engagement claws inserted into the slit portion And having a plurality of receiving parts for receiving the energy director part, and storing the battery cell in a second case half that fits with the first case half; and
Fitting the first and second case halves in a state where the battery cells are stored in the first or second case halves;
Welding the first and second case halves by applying ultrasonic vibration to the energy director in the fitted first and second case halves;
A method of manufacturing a battery pack including : A first case half in which a plurality of energy director portions and slit portions welded by ultrasonic waves are alternately arranged on both sides facing each other on the open surface, or a plurality of engagement claws inserted into the slit portion And having a plurality of receiving parts for receiving the energy director part, and storing the battery cell in a second case half that fits with the first case half; and
By fitting the energy director part of the first case into the receiving part of the second case half, the battery cell is housed in the first or second case half, Fitting the first and second case halves;
In said mated first and second case half, the first only the outer peripheral edge portion of the case halves on by applying ultrasonic vibration, the receiving and melting a portion of said energy director unit Welding the first and second case halves by welding to a portion ;
A method of manufacturing a battery pack including :

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