JP2005340015A - Battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery pack with superior safety and shock resistance, while preventing an internal short-circuit and maintaining proper voltage characteristics even when shocked. <P>SOLUTION: The battery pack comprises a power generation element 1, lead wires for positive and negative electrodes electrically connected to the power generation element 1, a sheath material 4 of a metal lamination resin film; wherein metal lamination resin films of at least three sides around the power generation element 1 are sealed by thermal fusion, and then a battery where the lead wires for positive and negative electrodes are drawn to the outside through a portion thermally fused to the metal lamination resin film of the sheath material 4, a protective circuit element of the battery connected to the lead wires, and external connecting terminals connected to the protective circuit element are integrally formed by a molded resin. In the battery pack, buffering spaces 11 not filled by the molded resin in a part around the battery are formed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a battery pack, and in particular, a battery pack in which components of a sealed battery using a metal laminate resin film as an exterior material, a protection circuit for the battery, and an external connection terminal are integrated with a mold resin. In particular, the present invention relates to a battery pack that is less likely to cause an internal short circuit even when an impact is applied and that is excellent in safety and impact resistance.

  In recent years, there have been remarkable developments in technologies aimed at rapid performance enhancement, multifunctionalization, weight reduction, and miniaturization in portable electronic devices such as video cameras, headphone stereos, and portable terminals. Technical demands for higher energy and higher capacity of secondary batteries, which serve as drive power sources for time operation, are further increasing.

  In order to meet these technical demands, the development of non-aqueous electrolyte secondary batteries using materials that can occlude and release lithium, such as lithium metal, lithium alloys, or carbonaceous materials, is actively promoted. It became so. Among these non-aqueous electrolyte secondary batteries, from the technical point of view that reducing the volume occupied by elements other than the power generation element of the battery is advantageous for increasing the energy and size of the battery, it has been conventionally used as a battery exterior material. Instead of the metal cans made of iron or aluminum, a sealed battery using a metal laminate resin film that can be made thinner as an exterior material has been attracting attention.

  The metal laminate resin film is formed by laminating and laminating a soft metal film such as an aluminum foil capable of preventing permeation of electrolyte solution, moisture and gas, and a plastic film such as nylon, polyethylene, and polypropylene. . When this metal laminate resin film is used as a battery exterior material, a structure in which the outer periphery of the exterior material is sealed by thermal fusion in a state where the power generation element is accommodated is generally employed.

  In particular, if the metal laminate resin film is drawn to form a draw-formed part and the power generation element (battery body) is housed in the draw-formed part, it matches the shape of the housed power generation element. Since the drawn part is formed, it is possible to increase the proportion of the power generation element in the entire volume of the battery as compared with a mere bag-like exterior material, and there is an advantage that the battery capacity can be increased. .

  In addition, when using the said metal laminated resin film as a battery exterior material, the thickness can be made into about 0.1 mm-0.2 mm, and thinning compared with other exterior materials. Although it is possible, it is a problem that it is inferior to conventional metal cans from the viewpoint of strength. For example, when the battery is accidentally dropped, there is a problem that the battery is easily deformed by the impact force or a voltage is lowered due to a minute short circuit. In particular, when the degree of short circuit is large, the housed power generation element may generate heat or ignite. In addition, when a component having sharp corners comes into contact with the metal laminate resin film, the metal laminate resin film may be partially cut and the electrolyte filled inside may leak. .

  Thus, since the strength as a battery is insufficient, a conventional battery using a metal laminate resin film as an exterior material is a plastic with a protective circuit board having a function of preventing overcurrent and overvoltage being connected. It is usually used in a structure housed in a package made of metal.

  However, even when the battery pack has a structure in which the battery is covered with a plastic package in this way, the exterior material may be accidentally damaged when the battery body is incorporated into the plastic package, or the protective circuit board or metal There may be a problem caused by the low strength of the metal laminate resin film, such as the external lead terminal made of the metal being damaged by contacting the exterior material in the battery pack.

  In order to solve the above problems, for example, a battery structure in which a sealed battery using a metal laminate resin film, a protection circuit, and an external connection terminal are integrated with a mold resin is disclosed in Japanese Patent Application Laid-Open No. 2002-260609 ( For example, it is proposed by patent document 1).

  According to the battery structure according to the above proposal, since the battery body and the protective circuit board can be integrated by filling the mold resin after placing the battery body in a mold having a predetermined shape, when assembling the battery pack The possibility of damaging the battery is extremely low, and at the same time, a soft resin is filled between the protective circuit board, external lead terminal, external connection terminal and battery body without any gaps. Less damage.

In addition to the viewpoint of battery protection, the protection circuit board and external terminals can be integrated in one process, so the process can be simplified, and the entire battery can be covered by coating the battery body with an insulating mold resin. The effect which can strengthen the structural strength and insulation of this is acquired.
JP 2002-260609 A (Page 1-5, FIG. 1)

  However, the battery pack in which the surface of the battery body is coated with the mold resin as in the above-described conventional example has improved structural strength as compared with the battery using the laminate resin film as the exterior material. Compared with a battery pack having a structure incorporating, there is a portion that is weak in strength.

  That is, when the battery body is incorporated in a conventional plastic package, it is possible to give strength to the package itself by forming a reinforcing material such as a rib on the package, and between the package and the battery body. Since there is a gap, an impact force acting from the outside of the battery is carried on the reinforcing material, or is relaxed and absorbed by the gap, so that it is difficult to transmit directly to the battery.

  On the other hand, in the battery pack in which the battery main body is integrated with the mold resin, the battery is covered with the mold resin without a gap, so that the impact from the outside is directly transmitted to the battery, resulting in deformation or short circuit of the battery. There was a problem that the voltage was lowered due to discharge in a short time. For this problem, it is possible to increase the strength of the mold resin itself by increasing the resin mold thickness. However, in this case, the battery pack becomes excessive as compared with the dimensions of the battery body, which is disadvantageous for reducing the size and increasing the capacity of the battery, and lowering the volume efficiency of the battery. there were.

  The present invention has been made to solve the above-described conventional problems and problems, and includes a sealed battery using a metal laminate resin film as an exterior material, a protection circuit for the battery, and an external connection terminal. A battery pack that integrates parts with molded resin, and provides a battery pack with excellent safety and impact resistance as well as maintaining good voltage characteristics that are resistant to internal short-circuiting even when impact is applied. The purpose is to do.

  That is, the battery pack according to the present invention includes a power generation element, positive and negative electrode lead wires electrically connected to the power generation element, and a metal laminate resin film exterior material, and at least 3 around the power generation element. A battery in which the other metal laminate resin film is sealed by thermal fusion, and the positive and negative electrode lead wires are drawn to the outside via a portion thermally fused to the metal laminate resin film that is an exterior material; In the battery pack in which the protection circuit element of the battery connected to the lead wire and the external connection terminal connected to the protection circuit element are integrated with the molding resin, the molding resin is partly around the battery. A buffer space that is not filled is formed.

  That is, according to the present invention, in the battery pack in which the battery body and the accessory are integrated by the mold resin, a shock-absorbing space that is not filled with the mold resin is formed around the battery body, so that the impact force or the Even when a pressing force is applied, these impact force and pressing force are effectively mitigated and absorbed by the buffer space, so that it is difficult to transmit directly to the battery, and deformation and short circuit of the battery are effectively prevented. That is, in the present invention, by forming the buffer space, the battery pack as a whole can be cushioned, and a battery pack having a high resistance against an impact force or a pressing force acting from the outside can be supplied.

  In the battery pack, it is preferable that the metal laminate resin film as an exterior material is subjected to a drawing process to form a drawing part, and the power generation element is housed in the drawing part.

  According to the battery pack, the metal laminate resin film is subjected to a drawing process to form a drawing part, and the power generation element (battery body) is stored in the drawing part, and the shape of the power generation element to be stored is Since the matched drawn parts can be formed, it is possible to increase the proportion of the power generation element in the entire battery volume compared to a mere bag-shaped exterior material, and the effect of increasing the battery capacity is exhibited. The

  In the battery pack, it is preferable that a fusion part around the power generation element is bent in the direction of the power generation element, and the buffer space not filled with the mold resin is formed inside the bent portion.

  By forming a buffer space inside the bent portion of the fusion part as described above, in addition to absorbing and reducing the impact force etc. by the buffer space itself, the bent part of the metal laminate resin film constituting the heat fusion part It is also possible to obtain an effect of absorbing the impact force by utilizing the elastic force at.

  Furthermore, in the battery pack, it is preferable that the buffer space that is not filled with the mold resin is formed in the vicinity of a corner portion of the drawn portion of the metal laminate resin film.

  Here, when a battery pack is dropped due to an accident in handling, etc., it is unlikely that the battery pack will collide with the floor etc. over the entire plane of the battery pack. It is thought that there are many. In the case of the latter, since the corner portion (corner portion) of the battery first collides immediately after dropping, the battery corner portion becomes a location where the impact force is concentrated. For this reason, it is desirable to form a buffer space that is not filled with the molding resin in the vicinity of the drawn portion of the built-in battery or the corner portion of the battery pack.

  By forming the buffer space in the vicinity of the corner portion of the drawing portion as described above, the shock force acting on the corner portion of the particularly fragile battery can be effectively absorbed and relaxed by the buffer space. Since the impact force is not directly transmitted to the battery, a battery pack excellent in impact resistance and safety can be obtained.

  In the battery pack, the buffer space not filled with the mold resin may be formed along two side surfaces extending from the corner so as to surround the corner of the drawn portion of the metal laminate resin film. preferable.

  That is, it is difficult to specify which side of the two side surfaces constituting the corner portion of the draw-formed portion is subjected to the main impact force. Therefore, in the case where an impact force is applied to any side surface near the corner portion by forming a buffer space along the two side surfaces extending from the corner portion so as to surround the corner portion of the drawn portion as described above. However, since the impact force can be effectively absorbed and relaxed by the buffer space and the impact force is not directly transmitted to the battery, a battery pack excellent in impact resistance and safety can be obtained.

  As is clear from the above description, according to the present invention, a shock-absorbing space that is not filled with mold resin is formed around the battery body. However, since the impact force and the pressing force are effectively relaxed and absorbed by the buffer space, it is difficult to transmit directly to the battery, and deformation and short circuit of the battery are effectively prevented. Therefore, due to the cushioning property of the buffer space, it becomes a battery pack that is hard to be short-circuited internally when dropped and has high safety, and it is possible to supply a battery pack having strong impact resistance against impact force or pressing force acting from the outside. it can.

  Hereinafter, an example of an embodiment of a battery pack according to the present invention will be described more specifically with reference to the accompanying drawings.

  FIG. 1 is an exploded perspective view showing a state where a power generation element 1 and an exterior material 4 constituting a battery pack to which the present invention is applied are assembled. The power generation element 1 includes a negative electrode plate in which a negative electrode material is held on a negative electrode current collector that is a support, a positive electrode plate in which a positive electrode active material is held on a positive electrode current collector that is a support, and the negative electrode The separator is interposed between the plate and the positive electrode plate to hold the electrolytic solution and prevent a short circuit between the two electrodes. The negative electrode plate, the positive electrode plate, and the separator are all formed into a thin sheet shape or foil shape, and these laminated bodies are pressed around a predetermined winding axis and then pressed into a flat long cylindrical shape. Formed. The power generation element 1 is provided with a negative electrode lead 2 electrically connected to the negative electrode and a positive electrode lead 3 electrically connected to the positive electrode, both of which generate the power generation in a direction parallel to the winding axis. It extends from element 1.

  The power generation element 1 has a configuration in which a separator is disposed between a positive electrode plate and a negative electrode plate, and the separator holds the electrolytic solution. However, a solid electrolyte or gel-like material is interposed between the positive electrode plate and the negative electrode plate. It is also possible to employ a power generation element provided with an electrolyte.

  As the exterior material 4 that houses the power generation element 1, a metal laminate resin film that has been subjected to a drawing process is used. The metal laminate resin film is formed by bonding a thermoplastic metal film such as polyethylene, polypropylene, nylon, etc., for heat-sealing after housing the power generating element 1 to a soft metal thin film such as aluminum.

  As shown in FIG. 1, the method of housing the power generating element 1 in the metal laminate resin film exterior material 4 is to fold one side of the exterior material 4 on which the rectangular drawn portion 5 is formed, The power generation element 1 is accommodated so that the negative electrode lead 2 and the positive electrode lead 3 are pulled out from the opposite side to the opposite side, and the peripheral portions of the three sides other than the valley-folded side are thermally fused. It was set as the method of sealing automatically.

  Next, a method of incorporating the sealed battery in a battery pack to which the present invention is applied will be described. 2 shows the configuration of the sealed battery in which the power generating element 1 is accommodated in the drawing part 5 of the exterior material 4, FIG. 3 shows the external structure of the battery pack to which the present invention is applied, and FIG. A sectional view of a battery along IV-IV is shown. As shown in FIG. 2, a protective circuit board 6 having a function of preventing overcurrent and overvoltage is connected to the negative electrode lead 2 and the positive electrode lead 3 extending to the outside of the battery. Further, as shown in FIG. The external connection terminal 7 for connecting to is connected.

  Next, the sealed battery to which the protection circuit board 6 and the external connection terminal 7 are connected is set in a predetermined mold, and a mold resin heated to a high temperature and melted is filled in the mold. Thereafter, the mold resin is cooled and solidified to produce a battery pack to which the present invention is applied. At this time, in order to connect the external connection terminal 7 to an external device, a part is exposed from the battery pack and is resin-molded. Further, in order to dissipate the heat when the battery generates heat to the outside of the battery, it is desirable to expose the surface portion of the drawing part 5 that houses the power generating element 1.

  The mold resin to be filled is preferably a thermoplastic polyamide or polyester resin, and the mold is preferably made of metal in order to efficiently cool the mold resin.

  Next, embodiments to which the present invention is applied will be described more specifically with reference to the following examples and comparative examples.

[Example 1]
A power generation element 1 having a length of 39 mm, a width of 19 mm, and a thickness of 4 mm was prepared as the power generation element 1 of the sealed battery incorporated therein. The metal laminate resin film used as the exterior material 4 is an aluminum laminate film composed of three layers of a nylon layer having a thickness of 25 μm, a soft aluminum layer having a thickness of 40 μm, and a polypropylene layer having a thickness of 30 μm. Was drawn so that the outer side of the battery was outside the battery, and a rectangular drawn portion 5 was formed. As for the dimensions of the rectangular drawn portion 5, the long side was 40 mm, the short side was 20 mm, and the depth was 4 mm.

  Then, one of the short sides having a length of 20 mm was valley-folded, and the power generation element 1 was accommodated in a direction in which the external lead was drawn out from the side opposite to the side where the valley was folded. After injecting the electrolyte into the power generation element 1 housed, the three sides other than the folded side were heat-sealed and sealed. The heat fusion width of each side was set to 4 mm and heat fusion was performed. Further, the heat-sealed portions on the two sides other than the side to which the external leads 2 and 3 were fused were bent at the fusion end on the drawing portion 5 side. At this time, the heat-sealed part was bent toward the drawing part 5 so that the distance W between the upper end of one fusion part and the side surface of the drawing part 5 was 1 mm.

  Further, as shown in FIGS. 2 and 3, after the protective circuit board 6 and the external connection terminal 7 were connected to the sealed battery, four sides of the sealed battery were covered with a mold resin. At this time, the gap between the bent fused portion 4a and the drawn portion 5 is not filled with resin, and the gap having the V-shaped cross-sectional shape is buffered as shown in FIGS. Space 11 was designated.

  In the actual resin filling operation, a protrusion having the same shape as the gap (buffer space) 11 is formed inside the mold, and the bent portion (V-shaped cross section) of the heat-sealing portion is located in the protrusion portion. Thus, the molten resin was filled in the state where the battery shown in FIG. 2 was set. About the protection circuit board 6, after arrange | positioning in the upper part of the heat sealing | fusion part to which the external leads 2 and 3 were melt | fused, it was made the state in which the whole battery was covered with the mold resin 8. FIG. The thickness of the resin 8 to be molded is set to 4 mm, which is almost the same as the battery thickness. On the periphery of the draw molding portion 5, the vertical dimension of the resin-molded battery pack is 48 mm and the horizontal dimension is 26 mm. The side on which the protective circuit board 6 is located is resin-molded up to a portion having a distance of 5 mm from the drawn portion 5, while the other three sides are resin-molded to a portion having a distance of 3 mm from the drawn portion 5, Many battery packs according to Example 1 were manufactured.

[Example 2]
As shown in FIGS. 5, 6, and 7, the external leads 2 and 3 are not heat-sealed among the heat-sealed portions of the sealed battery in which the power generation element 1 is built in the drawing portion 5 of the exterior material 4. The side is bent at a right angle, and the bending position is set to a position 1 mm from the fusion end on the drawing portion 5 side, and the portion 3 mm outside from the position is bent in a state parallel to the side surface of the drawing portion 5, and the width A In the same manner as in Example 1, except that the buffer space 11a having a rectangular cross section of 1 mm is formed, the gap (buffer space) 11a between the bent portion and the drawn portion 5 is not filled with mold resin. Many battery packs according to Example 2 were manufactured by performing resin molding.

[Example 3]
As shown in FIGS. 8, 9, and 10, a mold resin is not filled in the gap between the bent fused portion 4 b and the drawn portion 5, and a buffer space 11 b having a width A of 1 mm is formed. A notch 9 having a width B of 2 mm is formed in advance in the fusion part 4b facing the part L (length 20 mm), and the central part L (long) of the gap 11b between the drawn part 5 and the bent fusion part 4b is formed. The range of 20 mm) is filled with resin, and on both sides of the filled range, the process is performed in the same manner as in Example 2 except that the range of 10 mm in length is the buffer space 11b not filled with resin. As a result, many battery packs according to Example 3 were manufactured.

[Example 4]
As shown in FIG. 11, the buffer space 11 b portion that is formed on the long side of the battery in the battery pack of Example 3 and that is not filled with the resin has the same cross-sectional shape along the draw-molded portion 5 and 2 mm on the short side. Extending, forming a buffer space also in a portion having a length of 2 mm from the corner of the drawn portion 5 to the short side, and surrounding the corner portion of the drawn portion 5 of the metal laminate resin film (exterior material) 4, Except that the buffer space 11c was formed along two side surfaces extending from the corners, all of the battery packs according to Example 4 were manufactured by processing in the same manner as in Example 3 and performing the resin mold 8.

[Example 5]
As shown in FIG. 12 and FIG. 13, the protrusions having the same shape as the inner side of the folded fusion part are not formed on the inner side of the mold, and the resin is filled also inside the folded fusion part. A resin mold 8 is carried out in the same manner as in Example 1 except that a through hole 12 having a diameter of 1.5 mm is formed in the vicinity of the corner C at both ends of the bent portion 4a, and this through hole 12 is used as a buffer space. Thus, a number of battery packs according to Example 5 were manufactured.

[Example 6]
As shown in FIGS. 14, 15 and 16, the fusion part 4c of the built-in sealed battery is not bent, and the fusion width of two sides other than the side where the external terminals 2 and 3 are fused is 3 mm. While cutting and covering the periphery of the sealed battery with the mold resin 8, a cylindrical protrusion having a diameter of 1.5 mm and a height of 2 mm is arranged on the mold portion corresponding to the four corners of the battery pack. The resin mold is used to form a non-through hole 13 having a diameter of 1.5 mm and a depth of 2 mm in the vicinity of the four corners of the battery pack, except that the non-through hole 13 is used as a buffer space. A large number of battery packs according to Example 6 were manufactured in the same manner as in Example 1 and integrally formed with the mold resin 8.

[Comparative Example 1]
The same process as in Example 1 was performed except that the projection having the same shape as the bent fused part was not formed on the inner side of the mold, and the mold resin was also filled inside the folded fused part. Many battery packs according to Comparative Example 1 were manufactured.

[Comparative Example 2]
Protrusions with the same shape as the bent fused part are not formed on the inner side of the mold, and all the processes are the same as in Example 2 except that the resin is also filled inside the bent fused part, and the mold resin is integrally formed. Many battery packs according to Comparative Example 2 were manufactured.

[Comparative Example 3]
Comparative Example 3 in which the projection for forming the buffer space was not formed on the inside of the mold and the buffer resin was not formed in the vicinity of the corner of the battery pack. Many battery packs according to the above were manufactured.

  In order to evaluate the impact resistance and battery characteristics of the battery packs according to Examples and Comparative Examples prepared as described above, 50 battery packs were prepared and subjected to a drop test. In this drop test, each battery pack is dropped onto the concrete from a height of 1 m onto the concrete. The pipe has an internal size of 10 cm wide and 1 cm high, and is molded by passing through it. Always hit the concrete first.

50 battery packs according to each of the examples and comparative examples were dropped, and among them, the battery surface temperature in the draw-formed part at the time when 10 minutes had passed after the fall increased by 10 ° C. or more and generated heat. The number of battery packs and the number of batteries in which the voltage when the battery packs were allowed to stand for one day after the drop test were reduced by 15% or more compared to before the test were counted, and the results shown in Table 1 below were obtained.

  As is clear from the results shown in Table 1 above, in the battery packs according to Examples 1 to 6 in which a buffer space that is not filled with mold resin is formed around a part of the battery, an impact force acts by a battery drop test. Even in this case, since this impact force is effectively relaxed and absorbed by the cushioning space having cushioning properties, it is difficult to transmit directly to the battery, and the short circuit of the battery is effectively prevented. None, and it was confirmed that they had excellent impact resistance and safety.

  On the other hand, in the battery packs according to Comparative Examples 1 to 3 that do not form the buffer space, the impact force due to the drop is directly transmitted to the battery main body, and thus the voltage drop due to the short circuit of the battery. The number of batteries that caused the increase.

  In addition, the battery packs according to Examples 1 to 3 are examples in which a buffer space is formed only on one side of the two sides forming the corner portion of the drawn portion 5, and a large scale that generates heat by the buffer space. Although no short circuit occurs, it can be seen that a slight short circuit that causes a voltage drop with time occurs slightly.

  In particular, the buffer space is formed on both sides including the apex of the corner portion, that is, the buffer space is formed along two side surfaces extending from the corner portion so as to surround the corner portion of the drawn portion 5. In the battery pack according to Example 4, the impact force is less likely to be transmitted to the corner portion because the buffer space is formed along the two side surfaces even when the impact force acts from any side direction. In addition, it is clear from the number of packs whose voltage dropped after being left that the number of micro short-circuits that do not cause heat generation is greatly reduced. From this, it can be said that it is further desirable to form buffer spaces on both sides including the vicinity of the apex of the corner portion, and to make it difficult for shocking external forces from various directions to propagate to the battery body side.

  Furthermore, instead of the continuous groove-shaped buffer space having a V-shaped or rectangular cross-sectional shape, the battery pack according to the fifth embodiment in which the buffer space is formed in the vicinity of the corner apex with the through-hole 12 having a predetermined diameter, or the non-through hole Also in the battery pack according to Example 6 in which the buffer space is formed near the corner apex by the hole 13, the number of voltage drops is relatively small, and the impact absorption is equal to or greater than the groove-shaped buffer space of Examples 1 to 4. It has been demonstrated that a relaxation effect can be obtained.

  Further, in the battery pack according to the fifth embodiment, the buffer space is created only in the vicinity of the corner corresponding to the bent portion of the exterior material that accommodates the built-in battery. Even in this case, relatively good results have been obtained, and it can be said that providing cushioning properties around the corners that are not surrounded by the fusion part leads to a large impact absorption mitigating effect.

  Further, in each of the above embodiments, the width of each buffer space and the inner diameter of the through hole or non-through hole are preferably in the range of 0.5 to 3 mm, and more preferably in the range of 0.5 to 1.5 mm. If the width or inner diameter of each buffer space is less than 0.5 mm, the impact absorption and relaxation effect of each buffer space is insufficient, while if it exceeds the upper limit, there is a space that does not participate in the battery reaction. It was confirmed that the battery volume increased relatively and the volumetric efficiency of the battery decreased.

The disassembled perspective view which shows the state which combines the electric power generation element and exterior material of the sealed battery incorporated in a battery pack. 1 is a schematic perspective view of a sealed battery incorporated in a battery pack according to Embodiment 1. FIG. 1 is a schematic perspective view of a battery pack according to Embodiment 1. FIG. Sectional drawing of the IV-IV arrow direction in FIG. 4 is a schematic perspective view of a sealed battery incorporated in a battery pack according to Embodiment 2. FIG. 3 is a schematic perspective view of a battery pack according to Embodiment 2. FIG. Sectional drawing of the VII-VII arrow direction in FIG. 6 is a schematic perspective view of a sealed battery built in a battery pack according to Embodiment 3. FIG. 4 is a schematic perspective view of a battery pack according to Embodiment 3. FIG. Sectional drawing of the XX arrow direction in FIG. 6 is a schematic perspective view of a battery pack according to Embodiment 4. FIG. 6 is a schematic perspective view of a battery pack according to Embodiment 5. FIG. Sectional drawing of the XIII-XIII arrow direction in FIG. 10 is a schematic perspective view of a sealed battery incorporated in a battery pack according to Embodiment 6. FIG. 10 is a schematic perspective view of a battery pack according to Embodiment 6. FIG. Sectional drawing of the XVI-XVI arrow direction in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electric power generation element, 2 ... Negative electrode lead, 3 ... Positive electrode lead, 4 ... Exterior material (Metal laminated resin film, 4a, 4b, 4c ... Fusion part, 5 ... Drawing molding part, 6 ... Protection circuit board, 7 ... External Connection terminal, 8 ... Mold resin, 9 ... Notch, 11, 11a, 11b, 11c ... Buffer space, 12 ... Through hole (buffer space), 13 ... Non-through hole (buffer space), C ... Corner (corner) ).

Claims (5)

A power generation element, positive and negative lead wires electrically connected to the power generation element, and a metal laminate resin film exterior material, and at least three metal laminate resin films around the power generation element are heat-sealed And the battery connected to the lead wire, the positive and negative electrode lead wires being pulled out to the outside through a portion that is thermally fused to the metal laminate resin film that is an exterior material. In the battery pack in which the protective circuit element and the external connection terminal connected to the protective circuit element are integrated with the mold resin, a buffer space that is not filled with the mold resin is formed around the battery. A battery pack characterized by 2. The battery pack according to claim 1, wherein the metal laminated resin film as an exterior material is subjected to a drawing process to form a drawing part, and the power generation element is accommodated in the drawing part. . The fusion-bonding portion around the power generation element is bent in the direction of the power generation element, and the buffer space that is not filled with mold resin is formed inside the bent portion. Battery pack. The battery pack according to any one of claims 1 to 3, wherein the buffer space that is not filled with a mold resin is formed in the vicinity of a corner portion of the drawn portion of the metal laminate resin film. The buffer space that is not filled with mold resin is formed along two side surfaces extending from the corner so as to surround the corner of the drawn portion of the metal laminate resin film. 4. The battery pack according to any one of 3.

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