JP2006228714A - Battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase impact strength of a cover fit to the opening of a covering material in a battery pack in which a battery element is housed in the covering material. <P>SOLUTION: The battery element is housed in the hard covering material 1 having a first opening and a second opening at both ends, and a first cover and a second cover manufactured by resin molding are fitted to the first opening and the second opening. The second cover 3 has one or two or more through holes 32 filling resin between the second cover 3 and the battery element, and a groove 33 installed on the surface facing the battery element. When resin is filled between the second cover 3 and the battery element through the through hole, resin is filled in the groove installed on the surface facing the battery element and cured. It is therefore possible to ensure anchor effect. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a battery pack in which a battery element is housed in an exterior material.

  In recent years, portable electronic devices such as notebook personal computers, mobile phones, and PDAs (Personal Digital Assistants) have become widespread, and lithium ion batteries having advantages such as high voltage, high energy density, and light weight have been widely used as power sources.

  Further, as a countermeasure against liquid leakage that becomes a problem when using a liquid electrolyte, for example, a lithium polymer secondary battery using a gel polymer film obtained by impregnating a polymer with a nonaqueous electrolyte as an electrolyte, and an electrolyte Lithium polymer secondary batteries using an all-solid electrolyte have been put into practical use.

  A lithium polymer secondary battery includes a positive electrode, a negative electrode, and a polymer electrolyte, and a battery element in which electrode leads are led out from the positive electrode and the negative electrode, respectively, is configured as a cell covered with an exterior material such as an aluminum laminate. Furthermore, the cell is configured to be housed in a box-shaped plastic mold case composed of upper and lower cases together with a wiring board on which a circuit portion is mounted. Patent Document 1 below describes an example of a lithium ion polymer secondary battery having such a configuration.

JP 2002-260608 A

  In the conventional configuration in which the battery element is accommodated in the mold case, the thickness of the mold case is about 0.3 to 0.4 mm, and considering the double-sided tape for fixing and tolerance, the thickness of the cell is 0. The thickness increased by about 8 to 1 mm. In addition, a shape for ultrasonic welding of the upper and lower mold cases is required also in the outer peripheral direction, and therefore, a thickness of about 0.7 mm is required. As a result, the battery pack is forced to increase by 1.3 to 1.4 times the volume of the cell.

  In view of this, the present inventor has housed the battery element in a hard exterior material having first and second openings at both ends, and the first and second manufactured by resin molding with respect to the first and second openings. A battery pack is proposed in which two covers are fitted, and a circuit board to be joined to an electrode lead of a battery element is housed in a first cover fitted in a first opening.

  Since this battery pack is mainly handled as a single cell, drop strength is required. In particular, the second cover tends to come off more easily than the first cover that houses the circuit board.

  Accordingly, an object of the present invention is to improve the structural strength of a battery pack having a high volumetric efficiency that is configured by housing a battery element in a hard exterior material and fitting a resin molded cover to the opening of the exterior material. It is in providing the battery pack which can do.

In order to solve the above-described problem, the first invention is that a battery element is housed in a hard exterior material having first and second openings at both ends, and resin molding is performed with respect to the first and second openings. A battery pack in which the first cover and the second cover manufactured in the above are respectively fitted, and the circuit board to be joined to the electrode terminal lead of the battery element is housed in the first cover fitted into the first opening. In
The second cover
One or more through-holes filled with resin between the second cover and the battery element;
And a groove provided on a surface facing the battery element.

  In the first invention, the second cover includes one or more through-holes filled with resin between the second cover and the battery element, and a groove provided on the surface facing the battery element. Therefore, when resin is injected between the battery element and the second cover through the through hole, the resin is filled in the groove of the second cover provided on the surface facing the battery element. . Therefore, the resin can be cured in the groove of the second cover.

  In the first invention, it is preferable that a plurality of grooves are provided, and the plurality of grooves are connected or intersected with each other. Moreover, it is preferable that the groove | channel is provided in the substantially whole surface of the surface facing a battery element side. Moreover, it is preferable that a 2nd cover further has a recessed part in the surface on the opposite side to a battery element side. The through hole is preferably provided in the recess.

According to a second aspect of the present invention, a battery element is housed in a hard exterior material having first and second openings at both ends, and the first and second are manufactured by resin molding with respect to the first and second openings. In the battery pack in which the circuit boards are respectively fitted and the circuit board to be joined to the electrode terminal leads of the battery element is housed in the first cover fitted in the first opening.
The second cover
One or more through-holes filled with resin between the second cover and the battery element;
A side wall provided on the outer periphery of the surface on the battery element side,
The battery pack is characterized in that one or more notches are provided on the side wall.

  In the second invention, the second cover fitted into the second opening of the exterior material includes one or more through-holes filled with resin between the second cover and the battery element, and the battery element. Side wall provided on the outer peripheral portion of the side surface, and one or more notches are provided on the side wall, so that the resin filled from the through-holes is passed through the notches to provide a battery element. It can be hardened by flowing into the gap between the cover and the exterior material.

  In the second invention, it is preferable that the side wall is provided at a position that enters the inside from the outer periphery of the second cover by an amount corresponding to the thickness of the exterior material. Moreover, it is preferable that the second opening has a substantially rectangular shape in which the short side is expanded in an arc shape, and the notch is provided at least in a portion corresponding to the short side. Further, the second opening has a substantially rectangular shape in which the short side is expanded in an arc shape, and the side wall provided on the outer peripheral portion of the second cover is provided at least in a portion corresponding to the short side. It is preferable.

According to a third aspect of the present invention, a battery element is housed in a hard exterior material having first and second openings at both ends, and the first and second are manufactured by resin molding with respect to the first and second openings. In the battery pack in which the circuit boards are respectively fitted and the circuit board to be joined to the electrode terminal leads of the battery element is housed in the first cover fitted in the first opening.
The second cover
Two or more through-holes filled with resin between the second cover and the battery element;
A side wall provided on the outer periphery of the surface on the battery element side and a protrusion provided on the surface facing the battery element;
The battery pack, wherein the protrusion has a gap for the filled resin to enter when the resin is filled.

  In the third invention, the second cover fitted into the second opening of the exterior material is opposed to the battery element, with two or more through holes filling the resin between the second cover and the battery element. Provided with a protrusion having a void into which the filled resin enters, and by hardening the resin filled from the through hole, the bonding strength of the second cover can be improved. it can.

According to a fourth aspect of the present invention, a battery element is housed in a hard exterior material having first and second openings at both ends, and the first and second are manufactured by resin molding with respect to the first and second openings. In the battery pack in which the circuit boards are respectively fitted and the circuit board to be joined to the electrode terminal leads of the battery element is housed in the first cover fitted in the first opening.
The second cover
Two or more through-holes filled with resin between the second cover and the battery element;
A battery pack comprising: a side wall provided on an outer peripheral portion of a surface on the battery element side; and a fitting hole portion penetrating from the outer peripheral surface of the side wall toward the inner peripheral surface.

  In the fourth invention, the second cover fitted into the second opening of the exterior member is penetrated from the outer peripheral surface of the side wall toward the inner peripheral surface through the side wall provided on the outer peripheral portion of the battery element side surface. Since the filled resin enters the fitting hole, and the resin filled from the through hole is cured, the bonding strength of the second cover can be improved.

According to a fifth aspect of the present invention, the battery element is housed in a hard exterior material having first and second openings at both ends, and the first and second parts are manufactured by resin molding with respect to the first and second openings. In the battery pack in which the circuit boards are respectively fitted and the circuit board to be joined to the electrode terminal leads of the battery element is housed in the first cover fitted in the first opening.
The second cover
A side wall provided on the outer peripheral portion of the surface on the battery element side, and a protrusion for preventing removal provided on the outer peripheral surface of the side wall,
The battery pack is characterized in that the second cover is fitted so that the hard exterior material is pushed and spread by the protrusions for preventing the removal.

  In the fifth invention, the second opening is pushed and widened by fitting the second cover, in which the protrusion for preventing removal is provided on the outer peripheral surface of the side wall, into the second opening. As a result, the protrusions for preventing slipping can deform the hard exterior material of the second opening so that pressure is applied to the second cover.

According to a sixth aspect of the present invention, a power generation element in which a battery element is covered with a soft exterior material and three sides of the battery element are sealed is housed in a hard exterior material having first and second openings at both ends. The first and second covers manufactured by resin molding are fitted into the first and second openings, respectively, and the electrode of the battery element is fitted in the first cover fitted into the first opening. In the battery pack that stores the circuit board to be joined to the terminal lead,
The hard exterior material has a four-layer structure in which a first adhesive layer, a second adhesive layer, a metal layer, and a surface protective layer are sequentially laminated,
The second cover
A battery pack comprising: a side wall provided on an outer peripheral portion of a surface on the battery element side; a slit provided on an outer peripheral surface of the side wall; and a welding rib provided on a surface of the side wall facing the battery element. is there.

  In the sixth invention, by providing the slit in the second cover, the adhesive melted when the second cover and the hard exterior material are heat-welded is accumulated in the slit, and the high-quality exterior material and the second exterior material are collected. It is possible to prevent leakage from the gap between the covers to the outside. Moreover, by providing the welding rib, the welding area between the second cover and the hard exterior material can be increased.

  As described above, according to the first invention, the second cover is provided with a groove on the surface facing the battery element, and the groove is filled with resin and cured, so that an anchor effect is obtained. Can do. Accordingly, it is possible to suppress the second cover from falling off due to an external impact or the like.

  According to the second invention, the notch portion is provided in the side wall of the second cover, and the resin is allowed to flow into the gap between the battery element and the exterior material through the notch portion to be cured. Can be obtained. Accordingly, it is possible to suppress the second cover from falling off due to an external impact or the like.

  According to the third invention, for example, an L-shaped protrusion is provided on the surface of the second cover facing the battery element, and the resin is filled and cured, so that an anchor effect can be obtained. Accordingly, it is possible to suppress the second cover from falling off due to an external impact or the like.

  According to the fourth invention, since the resin is allowed to flow into the fitting hole provided from the outer peripheral surface of the side wall of the second cover toward the inner peripheral surface and hardened, an anchor effect can be obtained. Accordingly, it is possible to suppress the second cover from falling off due to an external impact or the like.

  According to the fifth aspect of the present invention, the protrusion of the second cover is provided on the side wall of the second cover and is fitted into the second opening so that the hard exterior material is deformed and pressure is applied. An anchor effect can be obtained without requiring filling. Accordingly, it is possible to suppress the second cover from falling off due to an external impact or the like.

  According to the sixth invention, since the slit is provided on the outer peripheral surface of the side wall of the second cover and the melted adhesive is accumulated, the leakage of the adhesive is prevented and the appearance and dimensional defects are suppressed. be able to. Moreover, since the welding rib can be provided on the side wall of the second cover to increase the welding area between the second cover and the hard exterior material, the bonding strength can be improved. Accordingly, it is possible to suppress the second cover from falling off due to an external impact or the like.

(1) First Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view showing one structural example of the battery pack according to the first embodiment of the present invention. This battery pack is, for example, a battery pack of a lithium ion polymer secondary battery having a square shape or a flat shape. As shown in FIG. 1, in this battery pack, a battery element is housed in an exterior material 1, and a top cover 2 and a bottom cover 3 are fitted into openings at both ends, respectively. The top cover 2 is provided with an opening 21 through which the contact portion of the circuit board accommodated in the top cover 2 faces the outside. Hereinafter, the opening on the side where the top cover 2 is fitted is referred to as a top side opening, and the opening on the side where the bottom cover 3 is fitted is referred to as a bottom side opening.

  Hereinafter, the battery element 4, the exterior material 1, the top cover 2, and the bottom cover 3 will be described with reference to FIGS.

<Battery element>
FIG. 2 is a perspective view showing an example of the appearance of the battery element 4 according to the first embodiment of the present invention. As shown in FIG. 2, the battery element 4 has, for example, a square shape or a flat shape, and a belt-like positive electrode and a belt-like negative electrode are laminated via a polymer electrolyte and / or a separator and wound in the longitudinal direction. At the same time, electrode leads 5a and 5b are led out from the positive electrode and the negative electrode, respectively.

  In the positive electrode, a positive electrode active material layer is formed on a strip-shaped positive electrode current collector, and a polymer electrolyte layer is further formed on the positive electrode active material layer. The negative electrode has a negative electrode active material layer formed on a strip-shaped negative electrode current collector, and a polymer electrolyte layer formed on the negative electrode active material layer. The positive and negative electrode leads 5a and 5b are joined to the positive electrode current collector and the negative electrode current collector, respectively. As the positive electrode active material, the negative electrode active material, and the polymer electrolyte, materials already proposed can be used.

The positive electrode can be composed of a metal oxide, a metal sulfide, or a specific polymer as the positive electrode active material depending on the type of the target battery. For example, in the case of constituting a lithium ion battery, as a positive electrode active material, Li _x MO ₂ (wherein M represents one or more transition metals, X is different depending on the charge / discharge state of the battery, and is usually 0.05 or more. Lithium composite oxide mainly composed of 1.10 or less) can be used. As the transition metal M constituting the lithium composite oxide, cobalt (Co), nickel (Ni), manganese (Mn) and the like are preferable.

Specific examples of such a lithium ion composite oxide include LiCoO ₂ , LiNiO ₂ , LiNi _y Co _1-y O ₂ (where 0 <y <1), LiMn ₂ O _{4 and the} like. Can do. These lithium composite oxides can generate a high voltage and have an excellent energy density. _{Further, TiS 2, MoS 2, NbSe} 2, V 2 O no lithium metal sulfides such as ₅ or may be used an oxide as the positive electrode active material. A plurality of these positive electrode active materials may be used in combination for the positive electrode. Further, when forming the positive electrode using the positive electrode active material as described above, a conductive agent, a binder or the like may be added.

As the negative electrode material, a material capable of doping and dedoping lithium can be used. For example, a non-graphitizable carbon material or a carbon material such as a graphite material can be used. More specifically, pyrolytic carbons, cokes (pitch coke, needle coke, petroleum coke), graphites, glassy carbons, organic polymer compound fired bodies (phenolic resin, furan resin, etc.) at an appropriate temperature. Carbon materials such as those obtained by firing and carbonization), carbon fibers, activated carbon, and the like can be used. Furthermore, as a material capable of doping and dedoping lithium, a polymer such as polyacetylene or polypyrrole or an oxide such as SnO ₂ can be used. When forming the negative electrode from such a material, a binder or the like may be added.

  The polymer electrolyte is one in which a polymer material, an electrolytic solution, and an electrolyte salt are mixed to form a gelled electrolyte into the polymer. The polymer material has a property compatible with the electrolytic solution, such as silicon gel, acrylic gel, acrylonitrile gel, polyphosphazene modified polymer, polyethylene oxide, polypropylene oxide, and composite polymers, cross-linked polymers, modified polymers thereof, etc. Alternatively, polymer materials such as poly (vinylidene fluoride), poly (vinylidene fluoride-co-hexafluoropropylene), or poly (vinylidene fluoride-co-trifluoroethylene), and mixtures thereof are used as the fluorine-based polymer. Is used.

As the electrolyte component, the above-described polymer material can be dispersed, and for example, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), or the like is used as an aprotic solvent. As the electrolyte salt, one that is compatible with a solvent is used, and a combination of a cation and an anion is used. As the cation, an alkali metal or an alkaline earth metal is used. As the anion, Cl ⁻ , Br ⁻ , I ⁻ , SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ^{− and the} like are used. Specifically, lithium hexafluorophosphate or lithium tetrafluoroborate is used in the electrolyte salt at a concentration at which it can be dissolved in the electrolytic solution.

<Exterior material>
FIG. 3 is a development view showing an example of the shape of the exterior material 1 that covers the battery element 4. As shown in FIG. 3, the exterior material 1 includes a soft laminate 1 a provided with a storage portion 15 for storing the battery element 4, and a soft laminate material 1 a overlaid on the soft laminate material 1 a so as to cover the storage portion 15. Hard laminate material 1b. A heat welding sheet 15 a is disposed on the outer surface at a position corresponding to the bottom surface of the storage unit 15. The storage portion 15 provided in the soft laminate 1 a is formed in a concave shape according to the shape of the battery element 4 by performing drawing with a mold in advance, for example.

  The soft laminate 1a is suitable for forming the storage portion 15 into which the battery element 4 is inserted by drawing, and is softer than the hard laminate 1b.

  FIG. 4 is a cross-sectional view illustrating a configuration example of the soft laminate material 1 a that constitutes the exterior material 1. The soft laminate 1a has a laminated structure having moisture resistance and insulating properties in which an adhesive layer 16a, a metal layer 17b, and a surface protective layer 18a are sequentially laminated, and the surface protective layer 18a is in contact with the hard laminate 1b.

  The adhesive layer 16a has a function of preventing the deterioration of the polymer electrolyte, and is a portion that is melted by heat or ultrasonic waves and fused to each other, and includes polyethylene (PE), non-axially stretched polypropylene (CPP), polyethylene terephthalate (PET), In addition to nylon (Ny), low density polyethylene (LDPE), high density polyethylene (HDPE), and linear low density polyethylene (LLDPE) can be used, and a plurality of types can be selected and used. The thickness of the adhesive layer 16a is, for example, about 30 μm.

  The metal layer 17a is made of a soft metal material and plays a role of protecting the contents by preventing the entry of moisture, oxygen and light in addition to improving the strength of the exterior material. As the soft metal material, aluminum is most preferable from the viewpoint of lightness, extensibility, cost, and ease of processing, and aluminum such as 8021O or 8079O is particularly preferable. Moreover, the thickness of the metal layer 17a is selected in the range of about 30 μm to 130 μm, for example.

  The surface protective layer 18a has a surface protective function. Polyolefin resins, polyamide resins, polyimide resins, polyesters and the like are used because of their beautiful appearance, toughness, and flexibility. Specifically, nylon (Ny), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polybutylene naphthalate (PBN) are used. Is also possible. The thickness of the surface protective layer 18a is selected, for example, in a range of about 10 to 30 μm.

  The hard laminate 1b maintains the shape after bending and can withstand deformation from the outside. The hard laminate 1b has a laminated structure in which an adhesive layer 16b, a metal layer 17b, and a surface protective layer 18b are sequentially laminated.

  The adhesive layer 16b and the surface protective layer 18b of the hard laminate 1b are the same as the soft laminate 1a. For example, a hard metal material is used for the metal layer 17b, and it is particularly preferable to use aluminum such as 3003-H18 and 3004-H18. In addition, the thickness of each layer of the soft laminate material 1a and the hard laminate material 1b is selected appropriately in consideration of the total thickness.

  The hard laminate material 1b is placed on the soft laminate material 1a so as to cover the opening surface of the storage unit 15. In this case, as shown in FIG. 3A, the positional relationship between the soft laminate material 1a and the hard laminate material 1b is shifted. Here, the soft laminate 1a has a top side long side 11a and a bottom side long side 12a having the same length, and has a left side short side 13a and a right side short side 14a having the same length. Similarly, the hard laminate 1b has a top-side long side 11b and a bottom-side long side 12b having the same length, and has a left-side short side 13b and a right-side short side 14b having the same length. The left and right indicate the positional relationship when viewed from the drawing.

  The lengths of the long sides 11b and 12b of the hard laminate 1b are such that the short sides 13b and 14b are in contact with each other or are opposed to each other with a slight gap in a state where the storage portion 15 in which the battery element 4 is stored is wrapped. It is set to be. The lengths of the long sides 11a and 12a of the soft laminate 1a are selected to be shorter than the lengths of the long sides 11b and 12b of the hard laminate 1b. For example, in a state where the storage portion 15 in which the battery element 4 is stored is wrapped. The short sides 13a and 14a are set to contact each other or face each other with a gap. Here, the gap between the soft laminates 1a is not limited to a slight width, and may have a certain width.

  The short sides 13a and 14a of the soft laminate 1a are slightly shorter than the short sides 13b and 14b of the hard laminate 1b. Therefore, the soft laminate material 1a and the hard laminate material 1b can be laminated so that only the hard laminate material 1b exists on the top side. In this case, it is possible to obtain an advantage that the peripheral surface of the top cover 2 provided in the opening on the top side can be thermally welded by the adhesive layer 16b of the hard laminate 1b. Even on the bottom side, the peripheral surface of the bottom cover 3 provided in the bottom side opening can be thermally welded by the adhesive layer 16b of the hard laminate material 1b so that the adhesive layer 16b of the hard laminate material 1b is exposed. You may do it.

<Top cover>
The top cover 2 is fitted into the top side opening of the exterior material 1 and closes the top side opening. The top cover 2 is provided with a circuit board, and electrode leads 5a and 5b drawn from the battery element 4 are connected to the circuit board.

  The circuit board is mounted with a protection circuit including a temperature protection element such as a fuse, PTC, and thermistor, an ID resistor for identifying the battery pack, and a plurality of, for example, three contact portions. Further, the protection circuit includes an IC for monitoring the secondary battery and controlling an FET (Field Effect Transistor), and a charge / discharge control FET.

  The PTC is connected in series with the battery element 4, and when the temperature of the battery element 4 becomes higher than the set temperature, the electrical resistance increases rapidly and substantially blocks the current flowing through the battery. A fuse and a thermistor are also connected in series with the battery element 4, and when the temperature of the battery element 4 becomes higher than the set temperature, the current flowing through the battery is cut off. Further, the protection circuit including the IC for monitoring the battery element 4 and controlling the FET and the charge / discharge control FET is dangerous if the terminal voltage of the battery element 4 exceeds 4.3V to 4.4V. Therefore, the voltage of the battery element 4 is monitored, and if it exceeds 4.3 to 4.4 V, the charge control FET is turned off and charging is prohibited. When the terminal voltage of the battery element 4 is overdischarged to below the discharge prohibition voltage and the secondary battery voltage becomes 0V, the battery element 4 may be in an internal short-circuit state and may not be recharged. If the voltage falls below the discharge inhibition voltage, the discharge control FET is turned off to inhibit discharge.

<Bottom cover>
FIG. 5A is a side view of the bottom cover 3. FIG. 5B is a plan view showing a surface facing the battery element 4. FIG. 5C is a plan view showing a surface opposite to the side facing the battery element 4. The bottom cover 3 closes the bottom side opening. When viewed from the direction opposite to the side facing the battery element 4, the bottom cover 3 has a rectangular shape as a whole, and both sides on the short side face outward. It swells to form an elliptical arc. A side wall 31 for fitting into the bottom side opening is provided on the surface of the bottom cover 3 on the battery element 4 side. The side wall 31 is provided along part or all of the outer periphery of the bottom cover 3. Further, the side wall 31 is provided at a position slightly inward from the outer periphery of the bottom cover 3, for example, at a position inward from the outer periphery of the bottom cover 3 by an amount corresponding to the thickness of the exterior material 1. Further, a pattern of grooves 33 is provided on the surface of the bottom cover 3 on the battery element 4 side. The pattern of the groove 33 is provided on a part or the entire surface of the bottom cover 3 on the battery element 4 side, preferably on the entire surface. By providing over the entire surface, the resin filled between the bottom cover 3 and the battery element 4 is also filled into the groove 33, whereby the anchor effect can be further improved.

  The pattern of the grooves 33 is, for example, a linear groove extending in one or more directions, and specifically, for example, a lattice pattern. The pattern of the grooves 33 is not limited to a regular pattern, and may be an irregular pattern. In order to further enhance the anchor effect, it is preferable to use a groove pattern in which a plurality of grooves 33 are connected or intersected with each other. As such a groove pattern, for example, a straight groove is formed into a T-shape. And a groove pattern in which straight grooves are crossed in a cross shape.

  Further, the bottom cover 3 is provided with one or more, preferably two or more through holes 32 penetrating from the surface facing the battery element 4 toward the opposite surface. When two or more through holes 32 are provided, at least one through hole 32 can be used for venting air between the battery element 4 and the bottom cover 3 at the time of resin injection. Fillability can be improved.

  Further, a recess 34 is provided on the surface opposite to the side facing the battery element 4. By providing the recess 34 as described above, the strength of the bottom cover 3 itself can be increased, and the falling off of the bottom cover 3 due to an external impact or the like can be further suppressed. In addition, when providing the recessed part 34 in the bottom cover 3, it is preferable to provide the through-hole 32 for inject | pouring hot-melt resin etc. in the recessed part 34. FIG. By doing so, it is possible to prevent an increase in the outer diameter of the battery pack even when the hot melt resin or the like protrudes from the through hole 32 after the hot melt resin or the like is injected and cured. it can.

  Next, a method for manufacturing a battery pack according to the first embodiment of the present invention will be described.

<Battery element manufacturing process>
First, for example, a positive electrode and a negative electrode on which gel electrolyte layers are formed on both sides, and a separator are sequentially laminated in the order of a negative electrode, a separator, a positive electrode, and a separator, and this laminate is wound around a flat plate core, A wound battery element 4 is produced by winding.

<Exterior material coating process>
Next, the storage portion 15 for storing the battery element 4 is formed on the soft laminate material 1a by deep drawing, for example. At this time, as shown in FIG. 3A, the storage portion 15 of the soft laminate 1a is formed, for example, at a position slightly shifted to the right side with respect to the center position. And the battery element 4 is accommodated in the accommodating part 15 formed in the soft laminate material 1a.

  Next, as shown in FIG. 3A, the hard laminate 1b is laminated at a position slightly shifted to the right with respect to the soft laminate 1a. Thereby, in the state where the soft laminate material 1a and the hard laminate material 1b are laminated, as shown in FIG. 3A, a left region where only the soft laminate material 1a is located and a right region where only the hard laminate material 1b is located Arise. As described later, the positions are shifted in this way after the ends of the soft laminate 1a and the hard laminate 1b are folded toward the outside of the bottom surface of the storage portion 15 of the soft laminate 1a, and then the soft laminate 1 This is because the adhesive layer 1a and the adhesive layer of the hard laminate 1b are bonded with a certain width.

  Next, in the state of arrangement as shown in FIG. 3A, the four sides around the opening of the storage portion 15 are thermally welded while reducing the pressure. In this case, the entire portion where the adhesive layers overlap may be heat-welded. In this way, the battery element 4 is sealed by thermally welding the periphery of the storage portion 15.

  Next, as shown in FIG. 3A, a heat welding sheet 15 a having a predetermined shape is provided outside the bottom surface of the storage unit 15. The heat welding sheet 15a is an auxiliary member for bonding the surface protective layers of the soft laminate material 1a by applying a high temperature. Preferably, the thickness is about 10 to 60 μm in terms of the total thickness, and a melting point of about 100 ° C. is used. The melting point of the heat welding sheet 15a is preferably such that the battery element 4 is not affected by heat.

  Next, as shown in FIG. 6, both ends of the soft laminate material 1a and the hard laminate material 1b, that is, the short sides 13a, 14a, 13b, and 14b are directed toward the outside of the bottom surface of the storage portion 15 of the soft laminate material 1a. Fold it in. Then, the end portions of the soft laminate material 1 a and the hard laminate material 1 b are heat welded, and the soft laminate material 1 a is heat welded to the outside of the bottom surface of the storage portion 15. Thereby, the soft laminate material 1a and the hard laminate material 1b are fixed in a closed state so as to enclose the storage portion 15 in which the battery element 4 is stored. That is, a top side opening and a bottom side opening are formed.

  As shown in FIG. 7, in the state where the battery element 4 is wrapped, the short side 13b and 14b of the hard laminate material 1b are in contact with each other, or the seam L1 formed by facing the end surfaces through a slight gap is formed. In addition, the short side 13a and 14a of the soft laminating material 1a are in contact with each other inside the hard laminating material 1b, or a seam L2 is formed in which the end faces are opposed to each other through a slight gap. Here, the case where the short sides 13a and 14a of the soft laminate 1a are in contact with each other or their end faces face each other with a slight gap is illustrated and described, but the short side of the soft laminate 1a The end surfaces of 13a and 14a may face each other through a gap having a certain width.

  As shown in FIG. 7, the surface protective layer 18a of the soft laminate material 1a is located in contact with the upper side of the heat welding sheet 15a. Therefore, the surface protective layer 18a has a structure sandwiching the heat welding sheet 15a, and the surface protective layers 18a can be bonded to each other by applying heat from the outside. Further, since the adhesive layers 16a and 16b of the soft laminate 1a and the hard laminate 1b face each other, the adhesive layers 16a and 16b can be bonded by applying heat from the outside.

  As described above, it is possible to manufacture a battery pack in which the laminate material also serves as an exterior material without using a resin box-shaped case and without arranging resin frames on both sides.

<Top cover mating process>
Next, as shown in FIG. 8, the electrode leads 5a and 5b are connected to the circuit board 22 by, for example, resistance welding or ultrasonic welding. Next, as shown in FIG. 9, the circuit board 22 is inserted into the open surface side of the top cover 2, and the top cover 2 is attached to the circuit board 22 so as to cover the circuit board 22. The top cover 2 is, for example, a resin molded product manufactured by injection molding or the like in a separate process.

  Note that a holding portion that holds the circuit board 22 horizontally is provided inside the top cover 2. Further, three openings 21 are provided on the top cover 2 at positions corresponding to the contact portions 23 of the circuit board 22. The contact portion 23 faces the outside through the opening 21. The width of the top cover 2 is selected to be slightly smaller than the inner dimension of the height of the opening on the end surface on the top side of the exterior material 1.

  Next, as shown in FIG. 10, the holder 24 is assembled to the top cover 2. The holder 24 is a resin molded product manufactured by, for example, injection molding in a separate process. Ribs 25a, 25b, and 25c that protrude toward the top cover 2 are provided at both ends and the center of the holder 24, respectively. Since the end surfaces of these ribs 25a, 25b and 25c serve as surfaces for receiving the circuit board 22 in the top cover 2, the circuit board 4 can be reliably supported.

  Next, as shown by an arrow R in FIG. 11, the fitted top cover 2 and holder 24 are rotated 90 ° clockwise by hand or a jig. As a result, the circuit board 22 that has been positioned horizontally is positioned vertically. In this case, since the circuit board 22 is sandwiched between the top cover 2 and the holder 24 and is not exposed to the outside, it can be rotated without touching the circuit board 4.

Next, as shown in FIG. 12, pushing the top cover 2 and the holder 24 while bending the electrode lead 5a and 5b toward the top-side opening (the direction of arrow S _1). Thereby, the top cover 2 and the holder 24 are fitted to the top side opening. Since the width of the top cover 2 is slightly smaller than the inner dimension of the opening as described above, the circuit board 22 is sandwiched in the space formed by the hard laminate 1b near the end face of the exterior material 1. The top cover 2 and the holder 24 can be stored.

<Bottom cover fitting process>
Next, as shown in FIG. 12, the side wall 31 of the bottom cover 3 is pushed toward the opening on the bottom side end face of the exterior material 1 (in the direction of the arrow S ₂ ). Thereby, the side wall 31 of the bottom cover 3 is fitted to the bottom side opening, and the bottom side opening is covered by the main body of the bottom cover 3. The bottom cover 3 is, for example, a resin molded product manufactured by injection molding in a separate process.

<Heat welding process>
Next, heat welding is performed while holding the entire length with a jig. That is, a heater block made of a metal such as copper is pressed from above and below near the top end of the exterior material 1 to thermally weld the peripheral surface of the top cover 2 and the adhesive layer on the inner surface of the hard laminate 1b. Similarly, the heater block is pressed from above and below near the bottom end of the exterior material 1 so that the peripheral surface of the bottom cover 3 and the adhesive layer on the inner surface of the hard laminate material 1b are thermally welded. Good.

<Resin injection process>
Next, the molten resin is filled between the battery element 4 and the bottom cover 3 through the through hole 32 and cured. Thereby, the bottom cover 3 is bonded to the end face of the battery element 4. The resin to be filled is not particularly limited as long as it has a low viscosity state at the time of casting, and for example, polyamide hot melt, polyolefin hot melt, nylon, PP, PC, ABS or the like is used. be able to.

Note that a molten resin may be filled between the top cover 2 and the battery element 4. In this case, one or more through holes may be provided in the top cover 2 and the molten resin may be injected from the through holes.
Through the above steps, the battery pack according to the first embodiment of the present invention is manufactured.

According to the first embodiment of the present invention, the following effects can be obtained.
The bottom cover 3 is provided with at least one through hole 32 for injecting hot-melt resin or the like, and a groove 33 is provided on the surface facing the battery element 4. 3, and hot melt resin (for example, polyamide resin) that can be molded at a lower temperature than the bottom cover 3 is filled and cured from the through hole 32 provided in the bottom cover 3. The bottom cover groove 33 is filled and cured. Thus, a so-called anchor effect can be achieved, and the bottom cover 3 is difficult to come off. In particular, when a pattern of grooves 33 connected or intersected in a T shape or a cross shape is formed, a high external impact resistance can be obtained. Further, even when the groove 33 pattern is formed on almost the entire surface of the bottom cover 3 on the battery element 4 side, high external impact resistance can be obtained.

(2) Second Embodiment Next, a second embodiment of the present invention will be described. In the second embodiment, a notch portion is provided in the outer peripheral portion of the bottom cover 3, and hot melt resin or the like is provided between the housing portion 15 housing the battery element 4 and the exterior material 1 through the notch portion. The anchor effect is obtained by allowing it to flow into a slight gap between the two and curing.

  Since things other than the bottom cover 3 are the same as those in the first embodiment described above, the bottom cover 3 will be described below.

  FIG. 13 shows an example of the shape of the bottom cover 3. As shown in FIG. 13, the bottom cover 3 closes the bottom side opening, and has a rectangular shape as a whole when viewed from the direction opposite to the side facing the battery element 4, and its short side Both sides of the side swell so as to form an elliptical arc toward the outside. A side wall 31 for fitting into the bottom side opening is provided on the surface of the bottom cover 3 on the battery element 4 side.

  The side wall 31 is provided along part or all of the outer periphery of the bottom cover 3. The height of the side wall 31 is selected to be equal to the depth of the bottom side opening of the exterior material 1, for example. With such a height, when the bottom cover 3 is fitted into the bottom opening, the end surface of the side wall 31 comes into contact with the bottom end surface of the battery element 4.

  Further, the side wall 31 is provided at a position slightly inward from the outer periphery of the bottom cover 3, for example, at a position inward from the outer periphery of the bottom cover 3 by an amount corresponding to the thickness of the exterior material 1. The side wall 31 is provided with one or more cutout portions 35. In the case where two or more cutout portions 35 are provided, the cutout portions 35 are provided at least on both ends in the longitudinal direction of the bottom cover 3, that is, on the short side of the bottom cover 3, for example.

  Further, the bottom cover 3 is provided with one or more, preferably two or more through-holes 32 penetrating from the surface facing the battery element 4 toward the surface opposite thereto. In the case where at least two through holes 32 are provided, at least one through hole 32 can be used for venting air between the battery element 4 and the bottom cover 3 at the time of resin injection. The filling property can be improved.

  Further, a groove 33 may be further provided on the surface of the bottom cover 3 on the battery element 4 side. By providing the groove 33 in this manner, the bottom cover 3 can be further prevented from falling off due to an external impact or the like. In addition, as a pattern of the groove | channel 33, the thing similar to the above-mentioned 1st Embodiment can be used. Furthermore, the bottom cover 3 may be further provided with a recess on the surface opposite to the battery element 4 side. By providing the recesses in this way, it is possible to further suppress the bottom cover 3 from falling off due to external impact or the like.

According to the second embodiment of the present invention, the following effects can be obtained.
The bottom cover 3 is provided with at least one through hole 32 for injecting hot-melt resin or the like, and one or two or more cutout portions 35 are formed on the side wall 31 of the outer peripheral portion that fits into the bottom side opening. Therefore, when hot melt resin or the like is injected from the through-hole 32, the injected hot melt resin or the like flows into the slight gap between the storage portion 15 and the exterior material 1 through the notch 35 and is cured. The Therefore, the anchor effect can be produced, and the bottom cover 3 can be prevented from dropping off due to an external impact or the like.

  When the battery element 4 is square or flat, the short side of the exterior material 1 swells outward when the battery element 4 is covered with the exterior material 1, so that there is a gap on the short side between the battery element 4 and the storage portion 15. Is formed. Therefore, when the battery element 4 is rectangular or flat, the hot melt resin or the like is provided between the storage portion 15 and the exterior material 1 by providing the cutout portions 35 of the side wall 31 at least on both short sides of the storage portion 15. The resin can be poured more easily between them. That is, the anchor effect can be further enhanced, and the bottom cover 3 can be further prevented from falling off due to an external impact or the like.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited only to these Examples.

  First, an example and a comparative example for verifying the effect of the groove 33 of the bottom cover 3 provided on the surface facing the battery element 4 will be described. FIGS. 14-20 is a perspective view for demonstrating the shape of Examples 1-8 and the bottom cover 3 of a comparative example. 14 to 18 show the shape of the surface on the side facing the battery element 4, and FIGS. 19 and 20 are perspective views showing the shape of the surface on the side opposite to the side facing the battery element 4. is there.

Example 1
First, the bottom cover 3 having the shape shown in FIGS. 14 and 19 was produced. That is, as shown in FIG. 14, one linear groove 33 extending from one side to the other side in the longitudinal direction was provided on the surface of the bottom cover 3 on the battery element 4 side. On the other hand, on the surface opposite to the battery element 4 side, as shown in FIG. 19, a recess 34 having a uniform depth extending from the center toward the outer peripheral portion was provided.

  Next, after the battery element 4 is stored in the exterior material 1, the short side of the exterior material 1 is folded toward the outside of the bottom surface of the storage unit 15 provided in the soft laminate material 1 a, While heat-welding the side, the exterior material 1 was heat-welded to the bottom surface of the storage portion 15 provided in the soft laminate material 1a. Thereby, a top side opening and a bottom side opening are formed. Thereafter, the top cover 2 was fitted into the top side opening of the exterior material 1, and the bottom cover 3 was fitted into the bottom side opening.

  Next, the heater block was pressed from the top and bottom in the vicinity of the top end of the exterior material 1 to thermally weld the peripheral surface of the top cover 2 and the adhesive layer 16b on the inner surface of the hard laminate material 1b. Next, hot melt resin was injected from the through hole 32 provided in the bottom cover 3 and cured. The intended battery pack was obtained through the above steps.

Example 2
First, as shown in FIG. 15, all the same as Example 1 except that two linear grooves 33 extending from one side to the other side in the longitudinal direction are provided on the surface on the battery element 4 side of the bottom cover 3. Similarly, a bottom cover was produced. A battery pack was obtained in the same manner as in Example 1 except that this bottom cover 3 was used.

Example 3
First, as shown in FIG. 16, two linear grooves 33 extending from one side of the longitudinal direction to the other side and one side from the short side to the other side are formed on the surface of the bottom cover 3 on the battery element 4 side. A bottom cover 3 was produced in the same manner as in Example 1 except that a plurality of linear grooves 33 extending in the same manner were provided so as to be connected in a T shape. A battery pack was obtained in the same manner as in Example 1 except that this bottom cover 3 was used.

Example 4
First, as shown in FIG. 17, the bottom cover 3 is the same as the first embodiment except that the grooves 33 are provided on almost the entire surface of the bottom cover 3 on the battery element 4 side. Was made. A battery pack was obtained in the same manner as in Example 1 except that this bottom cover 3 was used.

Example 5
First, as shown in FIG. 20, the bottom cover 3 was produced in the same manner as in Example 1 except that the concave portion 34 was not provided on the surface opposite to the battery element 4 side, and the surface was flat. . A battery pack was obtained in the same manner as in Example 1 except that this bottom cover 3 was used.

Example 6
First, as shown in FIG. 20, the bottom cover 3 was produced in the same manner as in Example 2 except that the concave portion 34 was not provided on the surface opposite to the battery element 4 side and the surface was flat. . A battery pack was obtained in the same manner as in Example 2 except that this bottom cover 3 was used.

Example 7
First, as shown in FIG. 20, the bottom cover 3 was manufactured in the same manner as in Example 3 except that the concave portion 34 was not provided on the surface opposite to the battery element 4 side and the surface was flat. . A battery pack was obtained in the same manner as in Example 3 except that this bottom cover 3 was used.

Example 8
First, as shown in FIG. 20, the bottom cover 3 was manufactured in the same manner as in Example 4 except that the concave portion 34 was not provided on the surface opposite to the battery element 4 side and the surface was flat. . A battery pack was obtained in the same manner as in Example 4 except that this bottom cover 3 was used.

Comparative Example First, as shown in FIG. 18, the bottom cover 3 is manufactured in the same manner as in Example 1 except that the groove 33 is not provided on the surface of the bottom cover 3 on the battery element 4 side and the surface is flat. did. A battery pack was obtained in the same manner as in Example 1 except that this bottom cover 3 was used.

  Next, a drop test of the battery pack obtained as described above was performed. The drop test was performed by dropping the battery pack 50 times from a position 1.5 m above the concrete with the bottom cover 3 side facing downward, and confirming the removal state of the bottom cover 3.

Table 1 shows the results of the drop test. Note that states A to F in Table 1 indicate the following states.
State A: The bottom cover 3 is not detached and the bottom cover 3 and the exterior material 1 are not peeled off.
State B: The bottom cover 3 does not fall off, but peeling between the bottom cover 3 and the exterior material 1 occurs in a range less than ¼ of the outer periphery of the bottom cover 3.
State C: The bottom cover 3 does not fall off, but the bottom cover 3 and the exterior material 1 are peeled from each other in a range from 1/4 to less than 1/2 of the outer periphery of the bottom cover 3.
State D: The bottom cover 3 does not fall off, but the bottom cover 3 and the exterior material 1 are peeled off in the range of 1/2 or more and less than 3/4 of the outer periphery of the bottom cover 3.
State E: The bottom cover 3 is not dropped, but the bottom cover 3 and the exterior material 1 are peeled off in a range of 3/4 or more of the outer periphery of the bottom cover 3.
State F: The bottom cover 3 falls off.

By comparing and examining the test results shown in Table 1, the following can be understood.
(1) By comparing the test results of Examples 1 to 8 and the comparative example, the anchor effect can be obtained by providing the groove 33 on the surface on the side facing the battery element 4, and due to external impact. It can be seen that the bottom cover 3 can be prevented from falling off.
(2) By comparing the measurement results of Examples 1 to 4 or Examples 5 to 8, the groove 33 is connected in a T shape or crossed in a cross shape, and the side facing the battery element 4 It can be seen that as the density of the grooves 33 on the surface to be increased is increased, the anchor effect can be further improved and the falling off of the bottom cover 3 due to external impact can be further suppressed.
(3) By comparing the measurement results of Examples 1 to 4 and Examples 5 to 8, by providing a recess 34 on the surface opposite to the side facing the battery element 4, a bottom cover due to external impact It can be seen that the dropout of 3 can be further suppressed.

  Next, an embodiment for verifying the effect of the cutout portion 35 of the bottom cover 3 provided on the surface facing the battery element 4 will be described. 21 and 22 are perspective views showing the shapes of the bottom covers 3 of the ninth and tenth embodiments, respectively.

Example 9
First, as shown in FIG. 21, a U-shaped side wall 31 is provided at both ends in the longitudinal direction on the surface of the bottom cover 3 on the battery element 4 side, and a notch 35 is provided on the side wall 31. The bottom cover 3 was produced in the same manner as in Example 6. A battery pack was obtained in the same manner as in Example 1 except that this bottom cover 3 was used.

Example 10
First, as shown in FIG. 22, the bottom cover 3 was manufactured in the same manner as in Example 9 except that the formation of the notch 35 was omitted. A battery pack was obtained in the same manner as in Example 1 except that this bottom cover 3 was used.

  Next, a drop test of the battery pack obtained as described above was performed. The drop test was performed in the same manner as the drop test for Examples 1 to 8 and the comparative example described above. Moreover, since the states A to F in Table 2 are the same as those in Table 1, description thereof will be omitted.

By comparing and examining the test results shown in Table 2, the following can be understood.
Comparing Example 9 and Example 10, it can be seen that by providing the notch 35 on the side wall 31, the anchor effect can be improved and the falling off of the bottom cover 3 due to external impact can be suppressed.

(3) Third Embodiment Next, a third embodiment of the present invention will be described. In the third embodiment, two or more through holes 32 for injecting hot melt resin or the like are provided in the bottom cover 3, and the surface of the bottom cover 3 on the side of the battery element 4 has a resin shape such as an L shape. Is provided with a protrusion 36 having a gap for allowing the filled resin to enter, and improves the filling property and injection stability of the hot melt resin and the like, and the bottom cover 3 and the hot melt resin. The joint strength can be improved.

  Since things other than the bottom cover 3 are the same as those in the first embodiment described above, the bottom cover 3 will be described below.

  FIG. 23 shows an example of the shape of the bottom cover 3. FIG. 24 is a perspective view showing an example of the shape of the bottom cover 3 according to the third embodiment. As shown in FIG. 23, the bottom cover 3 closes the bottom side opening, and has a rectangular shape as a whole when viewed from the direction opposite to the side facing the battery element 4, and its short side. Both sides of the side swell so as to form an elliptical arc toward the outside. A side wall 31 for fitting into the bottom side opening is provided on the surface of the bottom cover 3 on the battery element 4 side.

  The side wall 31 is provided along part or all of the outer periphery of the bottom cover 3. The height of the side wall 31 is selected to be equal to the depth of the bottom side opening of the exterior material 1, for example. With such a height, when the bottom cover 3 is fitted into the bottom opening, the end surface of the side wall 31 comes into contact with the bottom end surface of the battery element 4.

  Further, the side wall 31 is provided at a position slightly inward from the outer periphery of the bottom cover 3, for example, at a position inward from the outer periphery of the bottom cover 3 by an amount corresponding to the thickness of the exterior material 1. As shown in FIG. 23, the side wall 31 may be provided with one or more cutout portions 35 as required. In the case where two or more cutout portions 35 are provided, the cutout portions 35 are provided at least on both ends in the longitudinal direction of the bottom cover 3, that is, on the short side of the bottom cover 3, for example.

  Further, the bottom cover 3 is provided with two or more through holes 32 penetrating from the surface facing the battery element 4 toward the surface opposite thereto. In FIG. 23, two through holes 32a and 32b are provided. In this case, for example, the through hole 32a is for injecting hot-melt resin, and the through hole 32b is for removing air existing in the space between the battery element 4 and the bottom cover 3. Can do. With such a configuration, it is possible to prevent the filling of the hot melt resin from being hindered by the air in the space.

  Further, by injecting the hot melt resin through the air vent through hole 32b until the hot melt resin comes out, it is possible to visually confirm the injection state of the hot melt resin. Furthermore, since the injection amount of the hot melt resin varies, even if an appropriate amount is discharged, there is a possibility that the injection amount of the hot melt resin is small or an amount larger than the volume of the space portion is injected. is there. When there is only one through-hole 32, there is a possibility that the heat-welded portion between the bottom cover 3 and the exterior material 1 may be peeled off by injecting an amount larger than the volume of the space portion. For this reason, by providing the through hole 32b for venting air and making the injection amount of the hot melt resin larger than the volume of the space portion, it is possible to adjust the excess hot melt resin from the through hole 32b.

  Further, on the surface of the bottom cover 3 on the battery element 4 side, as shown in FIG. 24, for example, L-shaped protrusions 36a to 36d (hereinafter referred to as the protrusions 36 unless otherwise specified). 1 or 2 or more are provided. FIG. 25A is a cross-sectional view of the through hole 32a when the bottom cover 3 is fitted into the bottom side opening and heat-welded. FIG. 25B shows a state after the hot melt resin is injected from the through hole 32 a of the bottom cover 3. As shown in FIG. 25B, when the hot melt resin is injected from the through hole 32a of the bottom cover 3 and cured, the L-shaped protrusions 36a and 36b are caught by the resin. Thereby, the drop-off of the bottom cover 3 can be suppressed and the bonding strength can be improved.

  Note that, when the protrusion 36 is provided on the bottom cover 3 as described above, the bonding strength can be improved by the protrusion 36. Therefore, in the first and second embodiments, the battery element 4 side of the bottom cover 3 is provided. The groove 33 provided on the surface may not be provided. By not providing the groove 33, the flow of hot melt resin from the through hole 32a toward the through hole 32b is improved, and the resin filling property can be further improved.

  As the shape of the bottom cover having such a protrusion 36, a configuration as shown in FIGS. 26 and 27 may be adopted in addition to the bottom cover 3 shown in FIGS. In this case, as shown in FIG. 26 and FIG. 27, the bottom cover 3 may be provided with a notch as necessary.

  According to the third embodiment of the present invention, the following effects can be obtained. Since the bottom cover 3 is provided with two or more through holes 32 for injecting hot-melt resin or the like, and the surface of the bottom cover 3 on the battery element 4 side is provided with, for example, an L-shaped protrusion. Further, the filling property of the hot melt resin can be improved, and the joining property of the bottom cover 3 can be improved. In addition, it is possible to visually check the injection state of the hot melt resin, and further improve the filling property of the hot melt resin. For this reason, it is possible to suppress the bottom cover 3 from dropping off due to an external impact or the like.

  When the battery element 4 is square or flat, a gap is formed on the short side between the battery element 4 and the storage portion 15. Therefore, when the battery element 4 is rectangular or flat, the hot melt resin or the like is provided between the storage portion 15 and the exterior material 1 by providing the cutout portions 35 of the side wall 31 at least on both short sides of the storage portion 15. The resin can be poured more easily between them. That is, the anchor effect can be further enhanced, and the bottom cover 3 can be further prevented from falling off due to an external impact or the like.

  Note that the shape of the protrusion according to the third embodiment is not limited to the L shape as long as the structure has a gap for allowing the filled resin to enter when the resin is filled.

(4) Fourth Embodiment Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, two or more through holes 32 for injecting hot melt resin or the like are provided in the bottom cover 3, and the outer periphery of the side wall 31 provided on the surface of the bottom cover 3 on the battery element 4 side. A fitting hole is provided so as to penetrate from the surface to the inner peripheral surface, improving the filling property and injection stability of the hot melt resin and the like, and improving the bonding strength between the bottom cover 3 and the hot melt resin. It can be made to.

  FIG. 28 shows an example of the shape of the bottom cover 3. As shown in FIG. 28, the bottom cover 3 closes the bottom side opening, and has a rectangular shape as a whole when viewed from the direction opposite to the side facing the battery element 4, and its short side Both sides of the side swell so as to form an elliptical arc toward the outside. A side wall 31 for fitting into the bottom side opening is provided on the surface of the bottom cover 3 on the battery element 4 side. Moreover, the notch part 35 can be provided as needed.

  The side wall 31 is provided along part or all of the outer periphery of the bottom cover 3. The height of the side wall 31 is selected to be equal to the depth of the bottom side opening of the exterior material 1, for example. With such a height, when the bottom cover 3 is fitted into the bottom opening, the end surface of the side wall 31 comes into contact with the bottom end surface of the battery element 4.

  Further, the side wall 31 is provided at a position slightly inward from the outer periphery of the bottom cover 3, for example, at a position inward from the outer periphery of the bottom cover 3 by an amount corresponding to the thickness of the exterior material 1. As shown in FIG. 23, the side wall 31 may be provided with one or more cutout portions 35 as required. In the case where two or more cutout portions 35 are provided, the cutout portions 35 are provided at least on both ends in the longitudinal direction of the bottom cover 3, that is, on the short side of the bottom cover 3, for example.

  The side wall 31 of the bottom cover 3 is provided with bonding holes 37a to 37f (hereinafter, appropriately referred to as bonding holes 37 unless otherwise specified). One or more bonding holes 37 are provided in the long side portion of the side wall 31. Preferably, one or more bonding holes 37 are provided in each of the opposing long sides. In the bottom cover 3 having such a configuration, the hot melt resin injected from the through hole 32 a is filled while entering the bonding hole 37. For this reason, by hardening the hot-melt resin, the anchor effect can be obtained by the resin that has entered the bonding hole 37, the falling off of the bottom cover 3 can be suppressed, and the bonding strength can be improved.

  In the bottom cover 3 of the fourth embodiment, two or more through holes 32 are provided as in the third embodiment. For this reason, it can prevent that filling of hot-melt resin is prevented by the air of a space part. Further, by injecting the hot melt resin through the air vent through hole 32b until the hot melt resin comes out, it is possible to visually confirm the injection state of the hot melt resin.

According to the fourth embodiment of the present invention, the following effects can be obtained.
The bottom cover 3 is provided with two or more through holes 32 for injecting hot melt resin and the like, and a fitting hole through which hot melt resin can enter the side wall 31 of the battery element 4 of the bottom cover 3 is provided. Therefore, the filling property of the hot melt resin can be improved and the joining property of the bottom cover 3 can be improved. In addition, it is possible to visually check the injection state of the hot melt resin, and further improve the filling property of the hot melt resin. For this reason, it is possible to suppress the bottom cover 3 from dropping off due to an external impact or the like.

(5) Fifth Embodiment Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, the bottom cover 40 is joined to the exterior material 1 without injecting hot melt resin, and a protrusion 41 is provided on the side wall 41 of the bottom cover 40 to further prevent the bottom cover 40 from being attached to the exterior. By joining the material 1 with heat, the bonding strength is improved.

  Since the resin injection step is omitted and the configuration other than the configuration of the bottom cover 40 is the same as that in the first embodiment, the bottom cover 40 will be described below.

  FIG. 29 shows an example of the shape of the bottom cover 40. FIG. 30 is a schematic diagram showing in detail the protrusion 42a for preventing removal. As shown in FIG. 29, the bottom cover 40 closes the bottom side opening. When viewed from the opposite direction to the side facing the battery element 4, the bottom cover 40 has a rectangular shape as a whole. Both sides of the side swell so as to form an elliptical arc toward the outside. A side wall 41 for fitting into the bottom side opening is provided on the surface of the bottom cover 40 on the battery element 4 side.

  The side wall 41 is provided along part or all of the outer periphery of the bottom cover 40. The height of the side wall 41 is selected to be equal to the depth of the bottom side opening of the exterior material 1, for example. With such a height, when the bottom cover 40 is fitted into the bottom opening, the end surface of the side wall 41 comes into contact with the end surface on the bottom side of the battery element 4.

  Further, the side wall 41 is provided at a position slightly inward from the outer periphery of the bottom cover 40, for example, at a position inward from the outer periphery of the bottom cover 40 by an amount corresponding to the thickness of the exterior material 1. On the outer peripheral portion on the short side of the side wall 41, there are provided removal prevention protrusions 42a and 42b for fixing the bottom cover 40 (hereinafter referred to as removal prevention protrusions 42 unless otherwise specified). Yes.

  A plurality of convex portions 43 extending in the direction perpendicular to the long sides of the bottom cover 40 are provided on the surface of the bottom cover 40 facing the battery element 4 in order to improve the strength against pressure applied by the heater block during heat welding. In the bottom cover 40 of the fifth embodiment, since hot melt resin is not injected, it is not necessary to provide a through hole for resin injection and a space filled with the resin.

  At this time, as shown in FIG. 31, the arc-shaped portion on the short side of the side wall 41 provided in the bottom cover 40 and the arc-shape of the bottom-side opening formed by the exterior material 1 facing the arc-shaped portion. The part is formed with a difference in curve shape. In addition, before the bottom cover 40 is fitted, the outside of the protrusion 42 for preventing slipping is dimensioned so as to overlap the inner peripheral portion of the exterior material 1, for example, the most convex part of the protrusion for preventing slipping, The inner periphery of the exterior material is overlapped by about 0.05 mm to 0.1 mm.

  Such a bottom cover 40 is fitted to the bottom side opening of the exterior material 1 so that the exterior material 1 is pushed and spread by the protrusion 42 for preventing the removal. By fitting in this way, the exterior material 1 is deformed and lightly pressurized as shown in FIG. 32, and the bottom cover 40 is fixed to the bottom side opening. Subsequently, each of the long side portions of the bottom cover 40 is heated and pressed with a heater head to thermally weld the side wall 41 and the exterior material 1, thereby further improving the bonding strength.

  According to the fifth embodiment of the present invention, the following effects can be obtained. Since the injection process of hot melt resin is omitted, the manufacturing cost can be reduced. In addition, it is not necessary to invest in equipment for resin injection, and the effect of reducing personnel can be expected. In addition, the process can be simplified and productivity can be improved.

Furthermore, it eliminates the resin injection process and eliminates the need for structures such as through holes for resin injection and protrusions for improving the bondability with the resin, thereby simplifying the component structure and improving the accuracy of the component. Stability can be improved.
(6) Sixth Embodiment Next, a sixth embodiment of the present invention will be described. In the sixth embodiment, the bottom cover 3 according to the third embodiment described above is used for a battery cell with higher sealing performance.

  FIG. 33 shows the appearance of a battery pack 50 according to the third embodiment of the present invention. In this battery pack 50, a power generation element 53 is accommodated in a hard laminate film 51 as an exterior material, and a top cover 2 and a bottom cover 3 that are resin-molded covers are fitted to opening portions at both ends. A product label 55 is provided. In FIG. 33, parts common to those in the first to fifth embodiments described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 34 shows an exemplary configuration of the battery cell 54 according to the sixth embodiment of the present invention. The battery pack 50 includes a power generation element 53 whose battery elements are covered with a soft laminate material, a circuit board 22, a top cover 2, and a bottom cover 3, and the power generation element 53 is covered with a hard laminate material 51. It is a battery cell.

  The top cover 2 is a resin-molded cover that is provided at the top portion from which the positive electrode and the negative electrode are led out and fitted into the top opening of the battery cell. A holder 25a is further fitted to the top cover 2, and a circuit board 22 is disposed between the top cover 2 and the holder 25a. The bottom cover 3 is a resin molded cover that is fitted into the bottom opening of the battery cell 54. The top cover 2 and the bottom cover 3 are bonded to the battery cell 54 by heat welding or the like after being fitted into the opening of the battery cell 54.

  The circuit board 22 has a protection circuit mounted in advance, and the electrode leads 5a and 5b led out from the power generation element 53 and the protection circuit are connected by resistance welding, ultrasonic welding, or the like. The protection circuit includes a temperature protection element such as a PTC element or a thermistor that cuts off the current circuit of the battery when the battery becomes hot. Note that the circuit board 22 can be the same as that of the first to fifth embodiments described above, and thus detailed description thereof is omitted.

  Hereinafter, the configuration of the battery pack 50 will be described.

<Battery element>
The battery element 4 has, for example, a square shape or a flat shape, and a belt-like positive electrode and a belt-like negative electrode are laminated via a polymer electrolyte and / or a separator and wound in the longitudinal direction. Leads 5a and 5b are derived. As the battery element 4, since the same thing as 1st Embodiment can be used, detailed description is abbreviate | omitted.

<Exterior material>
The soft laminate 52 has a function of covering the battery element and preventing moisture from entering the inside, and is provided with a storage part for storing the battery element by deep drawing or the like. As the soft laminate material 52, the same material as that of the first embodiment can be used, and detailed description thereof will be omitted.

  The hard laminate material 51 further covers the power generating element 53 in which the battery element is covered with the soft laminate material 52, maintains the shape after bending, and can withstand deformation from the outside.

  As shown in FIG. 35, the hard laminate 51 has a moisture-proof and insulating laminated structure in which a first adhesive layer 51a, a second adhesive layer 51b, a metal layer 51c, and a surface protective layer 51d are sequentially laminated. Have.

  The metal layer 51c is made of a hard metal material, and aluminum, stainless steel, copper, titanium, tin, tin, nickel-plated iron, or the like can be used as appropriate. Among these, aluminum (Al) and austenitic stainless steel are most preferable, and it is particularly preferable to use aluminum such as 3003-H18, 3004-H18, and 1N30-H18, or stainless steel such as SUS304.

  The surface protective layer 51d can use the same material as in the first embodiment. The second adhesive layer 51b can be made of the same material as the adhesive layer 16b of the first embodiment.

  The first adhesive layer 51 a is for bonding the power generating element 53 and the hard laminate 51 covered with the soft laminate 52 without separately providing an adhesive member. As the first adhesive layer 51a, a resin material that is excellent in adhesiveness with Ny, PET, PEN and the like used as the surface protective layer of the soft laminate material 52 and whose melting temperature does not affect the battery element is used. Used. The first adhesive layer 51a is made of a resin material having a melting point lower than that of the material used for the second adhesive layer 51b.

  As the first adhesive layer 51a, specifically, ethylene vinyl alcohol resin (EVA), acid-modified polypropylene, ethylene vinyl acetate copolymer, ethylene acrylic acid copolymer, ethyl acrylate copolymer, methyl acrylate copolymer, methacrylic acid copolymer, Methyl methacrylate copolymer, polyacrylonitrile, polyamide resin, polyester resin, and ionomer can be used, and a plurality of types can be selected and used. The first adhesive layer 51a is a method in which these materials are bonded together as a film, a method in which a resin material (hot melt resin) melted by heat is applied and cooled, a hot melt resin is diluted with a solvent, and after application, The method of drying can be used.

  In such a hard laminate material 51, the first adhesive layer 51a is provided with a thickness of about 1 to 5 μm. Moreover, since the metal layer 51c has a function of using the outermost package of the battery pack 50 to maintain the strength of the battery pack 50, the metal layer 51c is used with a thickness of about 50 to 100 μm. The surface protective layer 51d is used in a thickness of about 9 to 15 μm, and the second adhesive layer 51b is used in a thickness of about 25 to 35 μm.

  The second adhesive layer 51b is used as a welding layer when the top cover 2 and the bomb cover 53 are thermally welded later. For this reason, a resin material having good adhesion to the top cover 2 and the bottom cover 3 is selected. The second adhesive layer 51 b also has a cushion function when the hard laminate material 51 is bonded to the power generation element 53. That is, when the soft laminate material 52, which is an exterior material of the power generation element 53, and the hard laminate material 51 are thermally welded via the first adhesive layer 51a, each laminate film has fine irregularities on the surface. Therefore, there are cases where the adhesiveness is not excellent. By providing the second adhesive layer 51b having a thickness of about 25 to 35 μm, the second adhesive layer 51b serves as a cushion, and satisfactorily bonds laminated films having fine irregularities on the surface. Can be made.

<Top cover>
The top cover 2 is fitted into the top opening of the battery cell 54 and closes the top opening. A circuit board 22 is accommodated in the top cover 2, and the circuit board 22 is held by incorporating a holder 24 manufactured so as to be fitted to the top cover 2. Electrode leads 5 a and 5 b drawn from the battery element 4 are connected to the circuit board 22. As the top cover 2, since the thing similar to 1st Embodiment can be used, detailed description is abbreviate | omitted.

<Bottom cover>
The bottom cover 3 is fitted into the bottom side opening of the battery cell 54 and closes the bottom side opening. When viewed from the direction opposite to the side facing the battery element 4, the bottom cover 3 has a rectangular shape as a whole. And both sides on the short side swell outwardly to form an elliptical arc. As the bottom cover 3, since the thing similar to 3rd Embodiment can be used, detailed description is abbreviate | omitted.

<Battery element manufacturing process>
Since the battery element 4 can be manufactured by the same process as in the first embodiment, detailed description thereof is omitted.

<Power generation element production process>
The battery element 4 produced in the same manner as in the first embodiment is packaged with a soft laminate 52 and molded to produce a power generation element 53 as shown in FIG.

  As shown in FIG. 37, the soft laminate material 52 has a recess 52a formed by deep drawing, and after the battery element 4 is accommodated in the recess 52a, the soft laminate material 52 is folded and the soft laminate material 52 is opened to the recess 52a. Cover the part. Next, the power generation element 53 is formed by sealing three sides of the battery element 4 except for the folded side by heat welding under reduced pressure.

  In the case of a battery using an electrolytic solution, the electrolytic solution is injected at this time. First, after heat-sealing two sides of the battery element except the folded side, a predetermined amount of electrolyte is injected from the remaining opening, and finally the opening is heat-welded. can get.

  The power generation element 53 may delete unnecessary portions of the top portion, which are the lead-out sides of the electrode leads 5a and 5b, by trimming in consideration of the subsequent manufacturing process. As shown in FIGS. 38A and 38B, by performing trimming along the line of reference symbol P, for example, interference between the top cover 2 and the soft laminate material 52 can be reduced.

<Battery cell production process>
The power generation element 53 thus produced is covered with a hard laminate material 51 to produce a battery cell 54. First, as shown in FIG. 39A, after placing the hard laminate 51 on the bottom surface of the power generation element 53, the hard laminate material 51 is bent so as to wrap the power generation element 53, and the hard laminate material 51 is bent on the upper surface of the power generation element 53. Exterior so that the ends meet. Next, a heater block is applied from the top and bottom surfaces of the power generation element 53, and heating is performed while applying pressure at a temperature at which the resin material of the first adhesive layer 51a is melted. The resin material of the first adhesive layer 51 a is melted to become an adhesive, and bonds the hard laminate material 51 and the power generation element 53. Thereby, the battery cell 54 whose cross section is shown in FIG. 39B is manufactured.

  Although the temperature of the heater block varies depending on the resin material of the first adhesive layer 51a, it is equal to or higher than the melting temperature of the resin material of the first adhesive layer 51a and is higher than the melting temperature of the resin material used for the second adhesive layer 51b. Also make the temperature low. Accordingly, only the resin material of the first adhesive layer 51a can be melted and bonded without melting the resin material of the second adhesive layer 51b.

  Further, when the heating temperature exceeds 120 ° C., it is considered that the battery element 4 is affected. For example, the separators 53a and 53b used in the battery element 4 are often made of polyethylene (PE). However, since the melting point of PE is about 120 ° C., it is considered that safety and battery function are lowered. From this, the temperature of the heater block is heated up to about 110 ° C.

  Note that the hard laminate material 51 may have a configuration as shown in FIGS. 40 to 43 as well as a configuration as shown in FIGS. 39A and 39B.

  40A and 40B are configurations in which the hard laminate material 51 is provided so as to cover the bottom surface portion of the power generation element 53 to form the battery cell 54, and a joint line of the hard laminate material 51 is provided on the upper surface portion of the battery cell 54. It is done. Note that the battery cell of FIG. 32 is molded so that the side portions are rounded, whereas the battery cell of FIG. 33 has a substantially rectangular cross section.

  41A and 41B are configurations in which the hard laminate material 51 is provided so as to cover one side portion of the power generation element 53 to form a battery cell 54, and the hard laminate material 51 is provided on one side portion of the battery cell 54. A seam is provided.

  42A and 42B show a configuration in which two hard laminate materials 51 are provided so as to cover both side portions of the power generation element 53 to form a battery cell 54. Hard laminates are formed on the upper surface portion and the bottom surface portion of the battery cell 54. A seam of the material 51 is provided.

  43A and 43B show a configuration in which two hard laminate materials 51 are provided so as to cover the upper surface portion and the bottom surface portion of the power generation element 53 to form a battery cell 54, and are hard on both side portions of the battery cell 54. A seam of the laminate material 51 is provided.

<Top cover mating process>
The top cover 2 accommodates the circuit board 22 and fits into the battery cell 54 with the holder 24 incorporated. The steps from joining the electrode leads 5a and 5b and the circuit board 22 to accommodating the top cover 2 in the top cover 2 and fitting the top cover 2 to the battery cell 54 are the same as in the first embodiment.

  The first adhesive layer 51a heated and melted when the hard laminate film 51 and the power generation element 53 are bonded is pressed by the side wall of the top cover 2 when the top cover 2 is fitted, and the battery cell 54 Move to the back. As described above, since the resin material having a lower melting temperature than the second adhesive layer 51b is used for the first adhesive layer 51a, when the hard laminate film 51 and the power generation element 53 are bonded, Only the first adhesive layer 51a is melted. Therefore, the first adhesive layer 51a can be moved without moving the second layer 73 used for bonding to the top cover 2, and the second adhesive layer 51b and the top cover face each other. Can be fitted in a state.

<Bottom cover fitting process>
The bottom cover 3 can be fitted in the same process as in the first embodiment. At this time, as in the case of the top cover 2 described above, the melted first adhesive layer 51a is pushed by the bottom cover 3 and moves to the back of the battery cell 54, and therefore the second adhesive layer 51b and the bottom The cover 3 can be fitted in a facing state.

<Heat welding process>
Thermal welding can be performed in the same process as in the first embodiment. At this time, the temperature of the heater head is set so as to be higher than that in the battery cell manufacturing process and equal to or higher than the melting temperature of the resin material of the second adhesive layer 51b. As a result, the second adhesive layer 51b that was not melted when the hard laminate material 51 is bonded to the power generation element is melted, and the top cover 2 and the bottom cover 3 and the second adhesive layer 51b are welded. Through the above steps, the battery pack 50 according to the sixth embodiment of the present invention is manufactured.

According to the sixth embodiment of the present invention, the following effects can be obtained.
Since the bottom cover 3 is provided with two or more through holes 32 for injecting hot-melt resin or the like, and the surface of the bottom cover 3 on the battery element 4 side is provided with, for example, an L-shaped protrusion. Further, the filling property of the hot melt resin can be improved, and the joining property of the bottom cover 3 can be improved. For this reason, it is possible to suppress the bottom cover 3 from dropping off due to an external impact or the like.

  In addition, by using a battery cell in which a battery element is packaged with a soft laminate and further packaged with a hard laminate, entry of moisture and the like can be prevented.

  In the sixth embodiment, it is possible to use not only the above-described bottom cover 3 but also the bottom covers having the shapes used in the first, second, fourth, and fifth embodiments.

(7) Seventh Embodiment Next, a seventh embodiment of the present invention will be described. In the battery pack 50 having the configuration used in the sixth embodiment, the seventh embodiment eliminates the leakage of adhesive and the warpage of the bottom cover that occur during the heat welding of the bottom cover, which has been a problem in the past. With the goal. When the bottom cover is thermally welded, for example, the first adhesive layer such as the EVA layer is melted. However, when the bottom cover is fitted, there is no space for the adhesive to escape as shown in FIG. 44A. The adhesive sometimes leaked to the outside through the gaps in the material. Also, the bottom cover is welded range W ₁ as narrow as about 0.7 to 1.0 mm, there are cases where bonding strength between the bottom cover and the exterior member becomes insufficient. Moreover, the component strength of the bottom cover itself is not stable, and it is difficult to suppress deformation at the time of dropping. Furthermore, as shown in FIG. 44B, there is a problem such as warping of parts.

  In the seventh embodiment, by providing a slit in the side wall of the bottom cover, it is possible to prevent the size and appearance defects even when the first adhesive layer is melted.

  In the seventh embodiment, the bottom cover is joined to the exterior material without injecting hot-melt resin, and a welding rib is provided on the side wall of the bottom cover so as to be thermally welded to the exterior material. Strength is improved.

  Since the resin injection step is omitted and the configuration other than the configuration of the bottom cover is the same as that of the above-described sixth embodiment, the bottom cover will be described below.

  FIG. 45A is a top view showing an example of the shape of the bottom cover 60 according to the seventh embodiment. FIG. 45B is a side view showing an example of the shape of the bottom cover 60 according to the seventh embodiment. This bottom cover 60 closes the bottom side opening and has a rectangular shape as a whole when viewed from the direction opposite to the side facing the battery element 4, and both sides on the short side are outward. It swells to form an elliptical arc. A side wall 61 for fitting into the bottom side opening is provided on the surface of the bottom cover 60 on the battery element 4 side.

Further, the side wall 61 is provided at a position slightly inward from the outer periphery of the bottom cover 60, for example, at a position inward from the outer periphery of the bottom cover 60 by an amount corresponding to the thickness of the hard laminate material 51. . The long side of the side wall 61 is provided with welding ribs 62a and 62b (hereinafter referred to as the welding rib 62 as appropriate unless otherwise specified), and is welded to the hard laminate 51 in a wider area. It is configured to be able to. For example, welding W ₂ may be about 1.3～2.0Mm.

  In addition, slits 63a and 63b (hereinafter, appropriately referred to as slits 63 if not particularly limited) are provided on the outer peripheral portion on the long side of the side wall 61 of the bottom cover 60. As shown in FIG. 46, when the bottom cover 60 is fitted, the slits 63a and 63b are located in the vicinity of the end of the hard laminate material 51. Therefore, when the bottom cover 60 and the hard laminate material 51 are welded, the bottom cover 60 is melted. When an adhesive such as EVA is about to leak to the outside through a gap between the bottom cover 60 and the hard laminate material 51, the adhesive is accumulated in the slits 63a and 63b.

According to the seventh embodiment of the present invention, the following effects can be obtained.
By providing the slit 63 in the bottom cover 60, it is possible to prevent the adhesive from leaking from the gap between the bottom cover 60 and the exterior material during heat welding. For this reason, a dimension and external appearance defect can be prevented and quality improvement can be aimed at. Moreover, since temperature conditions and pressurization conditions can be widely used, more stable heat welding can be performed. Furthermore, since the step of removing the leaked adhesive is not necessary, productivity can be improved and personnel can be reduced.

  Moreover, by providing the welding rib 62, the welding area of the bottom cover 60 and the hard laminate material 51 can be expanded, and the joining strength can be improved. Further, the strength of the bottom cover 60 itself can be improved, and deformation when the battery pack 50 is dropped can be suppressed. Further, it is possible to prevent the bottom cover 60 from warping.

  Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the first to seventh embodiments of the present invention described above, and is within the scope not departing from the gist of the present invention. Various modifications and applications are possible.

  For example, the numerical values given in the first to seventh embodiments are merely examples, and different numerical values may be used as necessary.

  In the first to seventh embodiments described above, the case where the present invention is applied to the battery pack in which the battery element is covered with the strip-shaped exterior material is shown as an example. However, the present invention is not limited to this example. The present invention can be applied to any battery pack in which battery elements are housed in an exterior material having openings at both ends. For example, the present invention can also be applied to a battery pack in which a battery element is housed in a tubular exterior material.

It is a disassembled perspective view which shows one structural example of the battery pack by 1st Embodiment of this invention. It is a perspective view which shows an example of the external appearance of the battery element by 1st Embodiment of this invention. It is an expanded view which shows an example of the shape of the exterior material which coat | covers a battery element. It is sectional drawing which shows one structural example of the soft laminate material which comprises an exterior material. It is the side view and top view which show an example of the shape of the bottom cover with which the battery pack by 1st Embodiment of this invention was equipped. It is a perspective view which shows an example of the external appearance of the battery element coat | covered with the exterior material. It is an expanded sectional view of the exterior material which coat | covered the battery element. It is a perspective view for demonstrating the manufacturing method of the battery pack by 1st Embodiment of this invention. It is a perspective view for demonstrating the manufacturing method of the battery pack by 1st Embodiment of this invention. It is a perspective view for demonstrating the manufacturing method of the battery pack by 1st Embodiment of this invention. It is a perspective view for demonstrating the manufacturing method of the battery pack by 1st Embodiment of this invention. It is a perspective view for demonstrating the manufacturing method of the battery pack by 1st Embodiment of this invention. It is a perspective view which shows an example of the shape of the bottom cover with which the battery pack by 2nd Embodiment of this invention is equipped. It is a perspective view which shows the bottom cover shape of the side facing a battery element. It is a perspective view which shows the bottom cover shape of the side facing a battery element. It is a perspective view which shows the bottom cover shape of the side facing a battery element. It is a perspective view which shows the bottom cover shape of the side facing a battery element. It is a perspective view which shows the bottom cover shape of the side facing a battery element. It is a perspective view which shows the bottom cover shape on the opposite side to the side facing a battery element. It is a perspective view which shows the bottom cover shape on the opposite side to the side facing a battery element. It is a perspective view which shows the bottom cover shape of the side facing a battery element. It is a perspective view which shows the bottom cover shape of the side facing a battery element. It is a schematic diagram which shows an example of the shape of the bottom cover with which the battery pack by 3rd Embodiment of this invention is equipped. It is a perspective view which shows an example of the shape of the bottom cover with which the battery pack by 3rd Embodiment of this invention is equipped. It is sectional drawing which shows the fitting state of the bottom cover with which the battery pack by 3rd Embodiment of this invention is equipped. It is a perspective view which shows an example of the shape of the bottom cover with which the battery pack by 3rd Embodiment of this invention is equipped. It is a perspective view which shows an example of the shape of the bottom cover with which the battery pack by 3rd Embodiment of this invention is equipped. It is a perspective view which shows an example of the shape of the bottom cover with which the battery pack by 4th Embodiment of this invention is equipped. It is a perspective view which shows an example of the shape of the bottom cover with which the battery pack by 5th Embodiment of this invention is equipped. It is a schematic diagram which shows an example of the shape of the bottom cover with which the battery pack by 5th Embodiment of this invention is equipped. It is a schematic diagram which shows the bottom cover and bottom side opening by 5th Embodiment of this invention. It is a schematic diagram which shows the fitting state of the bottom cover by 5th Embodiment of this invention. It is a schematic diagram which shows the structure of the battery pack by 6th Embodiment of this invention. It is a schematic diagram which shows the structure of the battery pack by 6th Embodiment of this invention. It is a schematic diagram which shows the structure of the hard laminate film by 6th Embodiment of this invention. It is a schematic diagram which shows the structure of the electric power generation element by 6th Embodiment of this invention. It is a schematic diagram which shows the structure of the electric power generation element by 6th Embodiment of this invention. It is a schematic diagram which shows the structure of the electric power generation element by 6th Embodiment of this invention. It is a schematic diagram which shows the structure of the battery cell by 6th Embodiment of this invention. It is a schematic diagram which shows the structure of the battery cell by 6th Embodiment of this invention. It is a schematic diagram which shows the structure of the battery cell by 6th Embodiment of this invention. It is a schematic diagram which shows the structure of the battery cell by 6th Embodiment of this invention. It is a schematic diagram which shows the structure of the battery cell by 6th Embodiment of this invention. It is a schematic diagram which shows the bottom cover shape by conventional embodiment. It is a schematic diagram which shows the bottom cover shape by 7th Embodiment of this invention. It is a schematic diagram which shows the bottom cover shape by 7th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exterior material 1a, 52 Soft laminating material 1b, 51 Hard laminating material 2 Top cover 3, 40 Bottom cover 4 Battery element 5a, 5b Electrode lead 31, 41, 61 Side wall 32, 32a, 32b Through-hole 33 Groove 34 Recess 35 Cut Notch 36, 36a, 36b, 36c, 36d Protrusion 37, 37a, 37b, 37c, 37d, 37e, 37f Joint hole 42a, 42b Protrusion for prevention 43 Protrusion 50 Battery pack 53 Power generation element 54 Battery cell 62a , 62b Welding rib 63a, 63b Slit

Claims (21)

The battery element is housed in a hard exterior material having first and second openings at both ends, and first and second covers manufactured by resin molding are fitted into the first and second openings, respectively. In the battery pack in which the circuit board to be joined to the electrode terminal lead of the battery element is housed in the first cover fitted into the first opening,
The second cover is
One or more through-holes filled with resin between the second cover and the battery element;
And a groove provided on a surface facing the battery element.   The battery pack according to claim 1, wherein a plurality of the grooves are provided, and the plurality of grooves are connected or intersected with each other.   2. The battery pack according to claim 1, wherein the groove is provided on substantially the entire surface facing the battery element side.   2. The battery pack according to claim 1, wherein the second cover further includes a recess on a surface opposite to the battery element side. 3.   The battery pack according to claim 4, wherein the through hole is provided in the recess. The battery element is housed in a hard exterior material having first and second openings at both ends, and first and second covers manufactured by resin molding are fitted into the first and second openings, respectively. In the battery pack in which the circuit board to be joined to the electrode terminal lead of the battery element is housed in the first cover fitted into the first opening,
The second cover is
One or more through-holes filled with resin between the second cover and the battery element;
A side wall provided on the outer periphery of the surface on the battery element side,
The battery pack according to claim 1, wherein the side wall is provided with one or more notches.   7. The battery pack according to claim 6, wherein the side wall is provided at a position that enters the inside from the outer periphery of the second cover by an amount corresponding to the thickness of the exterior material. The second opening has a substantially rectangular shape with a short side inflated in an arc shape,
The battery pack according to claim 6, wherein the notch is provided at least in a portion corresponding to the short side. The second opening has a substantially rectangular shape with a short side inflated in an arc shape,
The battery pack according to claim 6, wherein the side wall provided on the outer peripheral portion of the second cover is provided at least in a portion corresponding to the short side. The battery element is housed in a hard exterior material having first and second openings at both ends, and first and second covers manufactured by resin molding are fitted into the first and second openings, respectively. In the battery pack in which the circuit board to be joined to the electrode terminal lead of the battery element is housed in the first cover fitted into the first opening,
The second cover is
Two or more through-holes filled with resin between the second cover and the battery element;
A side wall provided on the outer periphery of the surface on the battery element side, and a protrusion provided on the surface facing the battery element,
The battery pack according to claim 1, wherein the protrusion has a gap for allowing the filled resin to enter when the resin is filled.   The battery pack according to claim 10, wherein one or more of the protrusions are provided.   The battery pack according to claim 10, wherein the protrusion is L-shaped.   The battery pack according to claim 10, wherein the side wall is provided with one or more notches. The battery element is housed in a hard exterior material having first and second openings at both ends, and first and second covers manufactured by resin molding are fitted into the first and second openings, respectively. In the battery pack in which the circuit board to be joined to the electrode terminal lead of the battery element is housed in the first cover fitted into the first opening,
The second cover is
Two or more through-holes filled with resin between the second cover and the battery element;
A battery pack, comprising: a side wall provided on an outer peripheral portion of the surface on the battery element side; and a fitting hole portion penetrating from the outer peripheral surface of the side wall toward the inner peripheral surface.   The battery pack according to claim 14, wherein the side wall is provided with one or more fitting holes. The battery element is housed in a hard exterior material having first and second openings at both ends, and first and second covers manufactured by resin molding are fitted into the first and second openings, respectively. In the battery pack in which the circuit board to be joined to the electrode terminal lead of the battery element is housed in the first cover fitted into the first opening,
The second cover is
A side wall provided on the outer peripheral portion of the surface on the battery element side, and a protrusion for preventing removal provided on the outer peripheral surface of the side wall,
The battery pack, wherein the second cover is fitted so that the hard exterior material is spread by the protrusions for preventing the removal. A convex portion is provided on the surface of the second cover facing the battery element,
The battery pack according to claim 16, wherein the convex portion is provided continuously from one long side of the side wall of the second cover toward the other long side. A power generating element in which a battery element is covered with a soft exterior material and three sides of the battery element are sealed is housed in a hard exterior material having first and second openings at both ends. The first and second covers manufactured by resin molding are respectively fitted to the second opening and the electrode terminal of the battery element in the first cover that is fitted to the first opening. In the battery pack that stores the circuit board to be joined to the lead,
The hard exterior material has a four-layer structure in which a first adhesive layer, a second adhesive layer, a metal layer, and a surface protective layer are sequentially laminated,
The second cover is
A side wall provided on the outer peripheral portion of the surface on the battery element side, a slit provided on the outer peripheral surface of the side wall, and a welding rib provided on a surface of the side wall facing the battery element. Battery pack to play.   The battery pack according to claim 18, wherein the melting point of the first adhesive layer is lower than the melting point of the second adhesive layer.   The battery pack according to claim 18, wherein the slit is provided in a long side portion of the second cover. The welding rib is provided on a long side portion of the second cover,
The battery pack according to claim 18, wherein the battery pack is provided with a length shorter than the slit.

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