JP5044934B2 - Battery pack - Google Patents

Description

  The present invention relates to a battery pack of a lithium ion secondary battery, for example.

  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.

  Furthermore, as a countermeasure against liquid leakage that becomes a problem when using a liquid electrolyte, for example, an electrolyte that uses a gel polymer film in which a polymer is impregnated with a nonaqueous electrolyte, or an all-solid electrolyte is used. A lithium ion polymer secondary battery using an electrolyte has been put into practical use.

  The polymer lithium ion battery includes a positive electrode, a negative electrode, and a polymer electrolyte, and has a battery cell configuration in which battery elements each having terminals derived from the positive electrode and the negative electrode are covered with an exterior film such as an aluminum laminate. Furthermore, it was set as the structure accommodated in the box-shaped plastic mold case which consists of an upper and lower case with the wiring board in which the battery cell and the circuit part were mounted. Patent Document 1 below describes an example of a lithium ion polymer secondary battery having such a configuration.

JP 2002-260608 A

  In this specification, a belt-like positive electrode and a belt-like negative electrode are laminated via a polymer electrolyte and / or a separator, wound in the longitudinal direction, and a terminal is derived from the positive electrode and the negative electrode, respectively. This is called a battery element. A battery element covered with a soft laminate film is called a power generation element, and a battery element covered with a hard laminate film is called a battery cell. Furthermore, what added the circuit board by which circuits, such as a protection circuit, were mounted with respect to the battery cell is called a battery pack.

  In the conventional configuration in which the battery element is housed in the mold case, the thickness of the mold case is in the range of about 0.3 to 0.4 mm, and considering the double-sided tape for fixing and tolerance, the thickness of the battery cell Thus, the thickness increased in the range of about 0.8 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 had to increase in volume in the range of 1.3 to 1.4 times the battery cell volume.

  As a method for solving this problem, the battery element is housed in a hard exterior material having openings on both sides, and a cover manufactured by resin molding is fitted into each opening, and then fitted into one opening. A battery pack in which a circuit board connected to an electrode terminal of a battery element is housed in a cover to be joined and a hot melt resin or the like is filled in the cover has been studied.

  However, in this battery pack, the resin is not sufficiently filled, a cavity is formed inside the first cover, and the circuit board is not sufficiently fixed by the resin. Has a problem that the circuit may be damaged.

  Accordingly, an object of the present invention is to provide a battery pack that reliably holds a circuit board and further improves mechanical strength.

  In order to solve the above-described problem, a first invention is a battery pack having a battery element of a secondary battery, wherein the battery element is housed in a hard exterior having first and second openings at both ends. The first cover is provided in the opening of 1, the second cover is provided in the second opening, the lead of the battery element and the circuit board are joined to each other, and the first cover is formed by mechanical engagement means. The circuit board is housed between the top cover and the holder, and the top cover is used for filling the space between the battery element and the first cover with resin. The holder has a resin filling hole, the holder is formed with protrusions at both ends, a notch is provided at the center of the protrusion, and one or more substrate support protrusions protruding toward the circuit board are formed near the center. Battery element and first cover Resin into the space is a battery pack, characterized in that it is filled between.

In addition, the second invention,
In a battery pack having a battery element of a secondary battery,
The battery element is housed in a hard exterior having first and second openings at both ends,
A first cover is provided in the first opening;
A second cover is provided in the second opening;
The battery element lead and the circuit board are joined together,
The first cover consists of a top cover and a holder,
The circuit board is stored between the top cover and the holder,
The top cover has a boss and a locking hole for coupling with the holder, the bosses are formed at both ends on the circuit board side, and the locking holes are provided on both side surfaces of the top cover,
Holder, respectively formed in the hole at both ends for passing the bosses Rutotomoni, on both sides of the holder, the hook used at the time of fitting of the top cover are respectively provided,
After the circuit board is stored between the top cover and the holder, the hook of the holder enters the locking hole of the top cover, and the top cover and the holder are engaged.
Boss of the top cover through the hole in the holder, the Rukoto dissolve the tip of the boss, a battery pack, wherein the top cover and the holder are joined.
The third invention is
In a battery pack having a battery element of a secondary battery,
The battery element is housed in a hard exterior having first and second openings at both ends,
A first cover is provided in the first opening;
A second cover is provided in the second opening;
The battery element lead and the circuit board are joined together,
The first cover consists of a top cover and a holder,
The circuit board is stored between the top cover and the holder,
Boss is formed at both ends of the top cover,
The holder has holes for penetrating the bosses at both ends.
The top cover boss penetrates into the hole of the holder, and the top cover and the holder are joined by dissolving the tip of the boss.
The battery pack is characterized by the above.

  As described above, the first invention has a top cover having a resin filling hole for filling the space between the battery element and the first cover with a resin, and both ends provided with notches in the central portion. A circuit board is accommodated between the protrusion and the holder having one or more substrate support protrusions, and the top cover and the holder are fitted by mechanical engagement means, so that a space between the battery element and the first cover is obtained. The circuit board can be reliably held by being filled with resin.

In the second and third inventions, the circuit board is provided between a top cover having bosses for fitting with the holder at both ends on the circuit board side and a holder having holes for penetrating the bosses at both ends. The circuit board can be securely held by being housed and by melting the tip of the boss and fitting the top cover and the holder.

  In the present invention, when the resin is filled, since the resin can be sufficiently filled inside the top cover by using a holder having a low resistance to the flow of the resin, the circuit board can be securely held, and the machine There is an effect that the strength can be improved.

  Further, according to the present invention, the resin flow can be unified when the resin is filled by providing the extending portions in the longitudinal direction from the protrusions at both ends of the holder. There is an effect that it can be filled.

  Furthermore, the present invention provides an extension part in the holder, so that when the top cover and the holder are fitted, the resin filling hole and the extension part face each other, so when a metal pin or the like is inserted from the resin filling hole There is an effect that the contact with the battery element can be suppressed and accidents such as a short circuit can be prevented.

  Furthermore, in the present invention, since the joining boss provided on the top cover is welded so that the top cover and the holder are fitted, the circuit board can be fixed more reliably. There is an effect that the terminal depth of the contact portion provided in can be made substantially constant.

  Furthermore, since the present invention welds both ends of the top cover, even when the top cover is warped, the warp can be suppressed by fitting the top cover and the holder. There is.

(1) First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration of an example of a battery pack to which the present invention can be applied, for example, a battery pack 1 of a lithium ion polymer secondary battery. The battery pack 1 mainly includes a battery cell 2, a top cover 3, a holder 4, a bottom cover 5, and a circuit board 9 accommodated between the top cover 3 and the holder 4. As an example, the battery cell 2 is obtained by coating a battery element with a hard laminate material as an exterior material.

  As will be described later, examples of the holder 4 include a holder 4a, a holder 4b, a holder 4c, a holder 4d, and a holder 4e. In the following description, the holders 4a, 4b, 4c, 4d, and 4e are described as the holder 4 when it is not necessary to particularly distinguish them.

  FIG. 2 shows the configuration of the battery element 6 used in the battery pack 1. This battery element 6 has a belt-like positive electrode 51, a separator 53a, a belt-like negative electrode 52 disposed opposite to the positive electrode 51, and a separator 53b, which are sequentially laminated and wound in the longitudinal direction, not shown. Gel electrolytes are formed on both surfaces of the positive electrode 51 and the negative electrode 52. Further, a positive electrode terminal 7a connected to the positive electrode 51 and a negative electrode terminal 7b connected to the negative electrode 52 are led out from the battery element 6 (hereinafter referred to as an electrode terminal 7 when a specific electrode terminal is not shown). Further, both the positive electrode terminal 7a and the negative electrode terminal 7b are covered with resin pieces 56a and 56b, respectively, in order to improve adhesion to a laminate film to be packaged later. In addition, when using electrolyte solution, the injection process of electrolyte solution is provided later.

  Hereinafter, the material of the battery element 6 will be described in detail.

[Positive electrode]
The positive electrode 51 is formed by forming positive electrode active material layers 51a containing a positive electrode active material on both surfaces of a positive electrode current collector 51b. The positive electrode current collector 51b is made of a metal foil such as an aluminum (Al) foil, a nickel (Ni) foil, or a stainless steel (SUS) foil.

  The positive electrode active material layer 51a includes, for example, a positive electrode active material, a conductive agent, and a binder. These are uniformly mixed to form a positive electrode mixture, and this positive electrode mixture is dispersed in a solvent to form a slurry. Next, the slurry is uniformly applied on the positive electrode current collector 51b by a doctor blade method or the like, dried at a high temperature, and the solvent is removed. Here, the positive electrode active material, the conductive agent, the binder, and the solvent only have to be uniformly dispersed, and the mixing ratio is not limited.

As the positive electrode active material, mainly 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 and 1.10 or less). A composite oxide of lithium and a transition metal is used. As the transition metal constituting the lithium composite oxide, cobalt (Co), Ni, manganese (Mn) or the like is used.

Specific examples of such a lithium composite oxide include LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , LiNi _y Co _1-y O ₂ (0 <y <1). A solid solution in which a part of the transition metal element is substituted with another element can also be used. Examples thereof include LiNi _0.5 Co _0.5 O ₂ and LiNi _0.8 Co _0.2 O ₂ . These lithium composite oxides can generate a high voltage and have an excellent energy density. _{Furthermore, 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.

  As the conductive agent, for example, a carbon material such as carbon black or graphite is used. As the binder, for example, polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene fluoride, or the like is used. Moreover, as a solvent, N-methylpyrrolidone etc. are used, for example.

  The positive electrode 51 has a positive electrode terminal 7a connected to one end of the positive electrode current collector 51b by spot welding or ultrasonic welding. The positive electrode terminal 7a is preferably a metal foil or a mesh-like one, but there is no problem even if it is not a metal as long as it is electrochemically and chemically stable and can conduct electricity. Examples of the material of the positive electrode terminal 7a include Al.

[Negative electrode]
The negative electrode 52 is formed by forming negative electrode active material layers 52a containing a negative electrode active material on both surfaces of a negative electrode current collector 52b. The negative electrode current collector 52b is made of, for example, a metal foil such as a copper (Cu) foil, a Ni foil, or a stainless steel foil.

  The negative electrode active material layer 52a includes, for example, a negative electrode active material, a conductive agent if necessary, and a binder. These are uniformly mixed to form a negative electrode mixture, and this negative electrode mixture is dispersed in a solvent to form a slurry. Next, this slurry is uniformly applied onto the negative electrode current collector 52b by a doctor blade method or the like, dried at a high temperature, and the solvent is blown off to form the negative electrode active material layer 52a. Here, the negative electrode active material, the conductive agent, the binder, and the solvent only have to be uniformly dispersed, and the mixing ratio is not limited.

As the negative electrode active material, lithium metal, a lithium alloy, a carbon material that can be doped / undoped with lithium, or a composite material of a metal material and a carbon material is used. Specific examples of carbon materials that can be doped / undoped with lithium include graphite, non-graphitizable carbon, graphitizable carbon, and the like. More specifically, pyrolytic carbons and cokes (pitch coke, needle coke). , Petroleum coke), graphites, glassy carbons, organic polymer compound fired bodies (phenol resins, furan resins, etc., calcined at an appropriate temperature), carbon fibers, activated carbon and other carbon materials are used. be able to. 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.

  In addition, various types of metals can be used as materials capable of alloying lithium, but tin (Sn), cobalt (Co), indium (In), Al, silicon (Si), and alloys thereof can be used. Often used. When metal lithium is used, it is not always necessary to use powder as a coating film with a binder, and a rolled Li metal plate may be used.

  As the binder, for example, polyvinylidene fluoride, styrene butadiene rubber or the like is used. Moreover, as a solvent, N-methylpyrrolidone, methyl ethyl ketone, etc. are used, for example.

  Similarly to the positive electrode 51, the negative electrode 52 has a negative electrode terminal 7b connected to one end of the negative electrode current collector 52b by spot welding or ultrasonic welding. The negative electrode terminal 52b is preferably a metal foil or a mesh-like one, but there is no problem even if it is not a metal as long as it is electrochemically and chemically stable and can conduct electricity. Examples of the material of the negative electrode terminal 52b include Cu and Ni.

  The positive terminal 7a and the negative terminal 7b are preferably derived from the same direction, but there is no problem regardless of the direction from which the positive terminal 7a and the negative terminal 7b are derived as long as no short circuit occurs. Moreover, the connection location of the positive electrode terminal 7a and the negative electrode terminal 7b is not limited to the above example as long as electrical contact is established, and the method of attachment is not limited to the above example.

[Electrolytes]
As the electrolyte, an electrolyte salt and a non-aqueous solvent that are generally used in lithium ion batteries can be used. Specific examples of the non-aqueous solvent include ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate, ethyl propyl carbonate, and carbonates thereof. And other solvents in which hydrogen is substituted with halogen. One of these solvents may be used alone, or a plurality of these solvents may be mixed with a predetermined composition.

As the electrolyte salt, one that dissolves in the non-aqueous 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, LiPF 6, LiBF 4, LiN} (CF 3 SO 2) 2, LiN (C 2 F 5 SO 2) 2, LiClO 4 and the like. The electrolyte salt concentration is not a problem as long as it can be dissolved in the above solvent, but the lithium ion concentration is in the range of 0.4 mol / kg or more and 2.0 mol / kg or less with respect to the nonaqueous solvent. Is preferred.

  When the gel electrolyte is used, the gel electrolyte is obtained by gelling an electrolyte solution in which the electrolyte and the electrolyte salt are mixed with a matrix polymer. The matrix polymer is not particularly limited as long as it is compatible with a nonaqueous electrolytic solution obtained by dissolving an electrolyte salt in a nonaqueous solvent and can be gelled. Examples of such a matrix polymer include a polymer containing polyvinylidene fluoride, polyethylene oxide, polypropylene oxide, polyacrylonitrile, and polymethacrylonitrile in repeating units. Such a polymer may be used individually by 1 type, and may mix and use 2 or more types.

[Separator]
The separator is made of, for example, a porous film made of a polyolefin-based material such as polypropylene (PP) or polyethylene (PE), or a porous film made of an inorganic material such as a ceramic nonwoven fabric. A structure in which a porous film is laminated may be used. Among these, polyethylene and polypropylene porous films are the most effective.

  In general, the thickness of the separator is preferably 5 to 50 μm, more preferably 7 to 30 μm. If the separator is too thick, the amount of the active material filled decreases, the battery capacity decreases, and the ionic conductivity decreases and the current characteristics deteriorate. On the other hand, if the film is too thin, the mechanical strength of the film decreases.

[Production of battery cells]
FIG. 3 is a development view showing an example of the shape of the exterior material that covers the battery element 6. The battery element 6 includes a soft laminate film 8a that has been previously drawn into a predetermined shape with a mold for housing the battery element 6, and a hard laminate material 8b that is disposed so as to cover the opening surface of the drawn portion. And sealed (the periphery of the drawn portion is thermally welded).

  FIG. 4 shows an example of the external appearance of the battery element 6 covered with the exterior material. Both ends of the hard laminate material 8b are bent toward the outside of the bottom surface of the drawn portion of the soft laminate film 8a, and are thermally welded to the outside of the bottom surface of the drawn portion.

  As the soft laminate film 8a, a laminate film having a configuration shown in FIG. 5 can be used. The soft laminate film 8a has a moisture-proof and insulating property in which a metal foil denoted by reference numeral 61 is sandwiched between an exterior layer 62 made of a resin film and an interior layer 63 (hereinafter appropriately referred to as a sealant layer) made of a resin film. It consists of a multilayer film having

  The metal layer 61 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. Particularly, aluminum having a thickness of about 30 μm to 130 μm such as 8021-O or 8079-O is used. It is preferable to use it. Further, the metal layer 61 and the exterior layer 62 and the metal layer 61 and the sealant layer 63 are bonded to each other through the adhesive layers 64 and 65. The adhesive layer 64 may be omitted as necessary.

  For the exterior layer 62, a polyolefin resin, a polyamide resin, a polyimide resin, a polyester, or the like is used because of its beauty in 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 exterior layer 62 has a thickness of about 10 μm to 30 μm.

  The sealant layer 63 is a portion that melts and fuses with heat or ultrasonic waves, and has a low density in addition to polyethylene (PE), non-axially oriented polypropylene (CPP), polyethylene terephthalate (PET), nylon (Ny). 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 most common configuration of the laminate film is: exterior layer / metal foil / sealant layer = Ny / Al / CPP. Moreover, not only this combination but the structure of the other general laminate film as shown below is employable. That is, exterior layer / metal film / sealant layer = Ny / Al / PE, PET / Al / CPP, PET / Al / PET / CPP, PET / Ny / Al / CPP, PET / Ny / Al / Ny / CPP, PET / Ny / Al / Ny / PE, Ny / PE / Al / LLDPE, PET / PE / Al / PET / LDPE, or PET / Ny / Al / LDPE / CPP. Of course, metals other than Al can be used as the metal foil.

  The hard laminate film 8b that appears on the outer surface is a hard film that maintains its shape after bending and can withstand deformation from the outside. The hard laminate film 8b has a polypropylene (PP) layer as an adhesive layer, a hard aluminum metal layer, and a nylon layer or PET (polyethylene terephthalate) layer as a surface protective layer. The hard aluminum metal layer is made of aluminum (JIS A3003P-H18) or (JIS A3004P-H18) without annealing, and has a thickness in the range of about 30 μm to 130 μm.

[Production of battery pack]
FIG. 6 shows a state in which the circuit board 9 is connected to the battery cell 2. A positive electrode terminal 7a and a negative electrode terminal 7b connected to the positive electrode and the negative electrode, respectively, are led out from one (top side) end face of the battery cell 2. The circuit board 9 is fixed to the positive terminal 7a and the negative terminal 7b by resistance welding, ultrasonic welding or the like. The circuit board 9 is mounted with a fuse, a PTC element (Positive Temperature Coefficient), a protection circuit including a temperature protection element such as a thermistor, an ID (IDentification) resistor for identifying a battery pack, and the like. . A plurality of, for example, three contact portions 10 are formed on the circuit board 9. The protection circuit is also applied to a protection circuit including an IC for monitoring a secondary battery and controlling an FET (Field Effect Transistor) and a charge / discharge control FET.

  The PTC element is connected in series with the battery element, and when the temperature of the battery 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, and when the temperature of the battery becomes higher than the set temperature, the current flowing through the battery is cut off. The protection circuit including the secondary battery monitoring and FET control IC and the charge / discharge control FET generates heat when the secondary battery terminal voltage exceeds 4.3V to 4.4V / secondary voltage.・ Because there is a possibility of danger such as ignition, the voltage of the secondary battery is monitored, and if it exceeds 4.3 to 4.4 V / secondary battery, the charge control FET is turned off and charging is prohibited. When the terminal voltage of the secondary battery is overdischarged to below the discharge prohibition voltage and the secondary battery voltage becomes 0V, the secondary battery is in an internal short-circuit state and cannot be recharged. Therefore, the secondary battery voltage is monitored, and when the voltage falls below the discharge inhibition voltage, the discharge control FET is turned off and discharge is prohibited.

  The bottom cover 5 is a resin molded product manufactured by injection molding or the like in a separate process, and is fitted into an opening on the side opposite to one opening of the hard exterior material into which the top cover 3 housing the circuit board 9 is fitted. Combined.

  The bottom cover 5 is not limited to this example, and may be molded by directly filling the opening with a hot-melt resin, for example, a polyamide-based resin.

  The top cover 3 is a resin molded product manufactured by injection molding or the like in a separate process. As shown in FIG. 7, the circuit board 9 is inserted from the release surface side of the top cover 3. The top cover 3 is attached to the circuit board 9 so as to cover the circuit board 9. Inside the top cover 3, a holding portion that holds the circuit board 9 horizontally is provided. A plurality of, for example, three openings 11 are formed at positions corresponding to the contact portions 10 on the upper surface of the top cover 3. The contact portion 10 faces the outside through the opening 11. The width of the top cover 3 is selected to be slightly smaller than the inner dimension of the opening height of the end surface on the top side of the battery cell 2.

  Further, in the vicinity of both ends of the top cover 3, a resin filling hole 12 a and a gas vent hole 12 b are provided at positions that do not overlap the circuit board 9. The size of the hole is, for example, in the range of φ0.8 mm to φ1.5 mm.

  The holder 4a is a resin molded product manufactured by injection molding or the like in a separate process. In FIG. 8, reference numeral 4a indicates a first example of the holder. Protrusions 13a and 13b for fitting with the top cover 3 are formed at both ends of the holder 4a, and a notch is provided at the center of each of the protrusions 13a and 13b.

  A substrate support protrusion 14a having a surface parallel to the longitudinal direction is formed near the center of the holder 4a. The circuit board 9 accommodated between the top cover 3 and the holder 4a can be supported by the circuit board supporting projection 14a when the top cover 3 and the holder 4a are fitted.

  FIG. 9 shows how the top cover 3 and the holder 4a are engaged. The holder 4a is engaged with the top cover 3 from below, and the circuit board 9 is accommodated between the top cover 3 and the holder 4a. In the first embodiment of the present invention, the top cover 3 and the holder 4a are engaged by the mechanical engagement means. That is, as shown in FIG. 10, holes 15a and 15b for locking are formed in the top cover 3, and a hook 16a formed at the tip of the protrusion 13a of the holder 4a enters the hole 15a, and enters the hole 15b. On the other hand, when the hook 16b formed at the tip of the protrusion 13b of the holder 4a enters, the top cover 3 and the holder 4a are engaged.

  Then, as indicated by an arrow R in FIG. 11, the engaged top cover 3 and holder 4a are rotated 90 ° clockwise by hand or jig. As a result, the circuit board 9 that has been positioned horizontally is positioned vertically. In this case, since the circuit board 9 is held between the top cover 3 and the holder 4a and is not exposed to the outside, it can be rotated without touching the circuit board 9.

  Thereafter, the engaged top cover 3 and holder 4a are stored in the battery cell 2, and hot melt resin is filled from the resin filling hole 12a. The circuit board 9 is held by the filled hot melt resin, and the mechanical strength is further improved.

  In FIG. 12, reference numeral 4b indicates a second example of the holder. The holder 4b is integrally formed with a substrate support protrusion 14b having a surface orthogonal to the longitudinal direction, and is formed in a trapezoidal shape such that the tip of the substrate support protrusion 14b is tapered. By doing so, the resistance of the substrate support protrusions with respect to the flow of the hot melt resin is reduced, so that the resin filling property can be improved.

  Next, a third example of the first embodiment of the present invention will be described. As shown in FIG. 13, the holder 4c as the third example is provided with extending portions 17a and 17b in the longitudinal direction from the protrusions at both ends of the holder. With the third holder 4c, the filling property of the hot melt resin can be further improved.

  That is, when the top cover 3 and the holder 4c are engaged, the extending portions 17a and 17b face the resin filling hole 12a and the gas vent hole 12b of the top cover 3. FIG. 14 is a perspective view of the vicinity of the resin filling hole 12a when the top cover 3 and the holder 4c are engaged, as viewed from the holder side. As shown in FIG. 14, since the extending portion 17a of the holder 4c is fitted so as to cover the resin filling hole 12a of the top cover 3, the flow is unified when the hot melt resin is filled, and the resin filling property is achieved. Will improve.

  In addition, by providing the extension portions 17a and 17b, even when a metal pin or the like is inserted from the resin filling hole 12a or the gas vent hole 12b, an accident such as a short circuit is prevented in order to suppress contact with the battery element 6. Can be prevented.

  A plurality of substrate support protrusions may be provided as necessary. For example, as shown in FIG. 15, the circuit board 9 can be more reliably supported by providing a plurality of board support protrusions 14a and 14b.

  Hereinafter, the holder which can be applied to the first embodiment of the present invention and the modified example of the first embodiment will be specifically described by way of examples.

  In addition to the holders 4a to 4c shown in FIGS. 8, 12 and 13, the holder 4d shown in FIG. 16 and the holder 4e shown in FIG. 17 are produced, and 50 battery packs 1 using each holder are manufactured, A drop test of the battery pack 1 was performed. In the drop test, the battery pack 1 is dropped from 1.5 m above the concrete with the top cover 3 facing downward, and the abnormality of the circuit board 9 and the degree of peeling between the top cover 3 and the exterior material are confirmed. did.

Example 1
As shown in FIG. 8, protrusions 13a and 13b having a notch in the center are provided at both ends, and a substrate support protrusion 14a having a surface in a direction parallel to the longitudinal direction is formed near the center. The prepared holder 4a was produced.

Example 2
As shown in FIG. 12, instead of the substrate support protrusion 14a, a substrate support protrusion 14b having a surface perpendicular to the longitudinal direction and having a trapezoidal shape with a tapered tip is provided. A holder 4b was produced in the same manner as in Example 1.

Example 3
As shown in FIG. 13, a holder 4c was produced in the same manner as in Example 2 except that extending portions 17a and 17b were provided in the longitudinal direction from the protrusions at both ends of the holder.

Comparative Example 1
As shown in FIG. 16, instead of the substrate support protrusion 14a, a holder 4d is produced in the same manner as in Example 1 except that a substrate support protrusion 14c having a rectangular surface perpendicular to the longitudinal direction is provided. did.

Comparative Example 2
As shown in FIG. 17, instead of the projections 13a and 13b, projections 13a ′ and 13b ′ are provided at both ends, and instead of the substrate support projection 14a, a rectangular surface is orthogonal to the longitudinal direction. A holder 4e was produced in the same manner as in Example 1 except that the substrate support protrusion 14c was provided.

  Table 1 below shows the results of the drop test.

  The number of circuit abnormalities indicates the number of abnormalities recognized on the circuit board 9. The state indicates the number of deformed top covers 3, and is further classified into states A to C depending on the degree of peeling between the top cover 3 and the exterior material. The state A indicates the number of the peeling that is 3/4 or more of the outer periphery including the case where the top cover 3 is removed. The state B shows the number of peeling of the top cover 3 that is 1/2 or more and less than 3/4 of the outer periphery. The state C shows the number of peeling of the top cover 3 that was less than ½ of the outer periphery. “* / 50” shown in Table 1 indicates the number of circuit board abnormalities or states A to C after 50 battery packs using each holder were manufactured and the drop test was continuously performed 50 times. Show. For example, in the case of the battery pack using the holder 4a to the holder 4d, there is no circuit board abnormality, and in the case of the battery pack using the holder 4e, circuit abnormality is recognized in 7 out of 50 battery packs. It shows that. Further, for example, when the battery pack using the holder 4a is dropped 50 times, the degree of peeling between the top cover 3 and the exterior material is not in the state A, the state B is 6 out of 50, the state It shows that 44 of 50 are for C.

  As a result of the drop test, in the case of the battery pack 1 using the holder 4a of Example 1, there is no battery pack in which an abnormality of the circuit board 9 is recognized, and peeling of the top cover 3 is also classified into the state A. There was no such detachment observed. In the case of the battery pack 1 using the holder 4b of Example 2 and the holder 4c of Example 3, no abnormality was found in the circuit board 9. Further, regarding the peeling of the top cover 3, one or several battery packs in which peeling in the state A was recognized were confirmed, but other than that, the peeling was relatively small.

  In the case of the battery pack 1 using the holder 4d of Comparative Example 1, no abnormality of the circuit board 9 was observed, but the degree of peeling of the top cover 3 was larger than that of the battery pack using the holders 4a to 4c. It was. In the case of the conventional battery pack 1 using the holder 4e of Comparative Example 2, a battery pack in which an abnormality of the circuit board 9 was recognized was confirmed. Further, among the five types of holders used in the drop test, when the holder 4e was used, the degree of peeling of the top cover 3 was the highest.

  When the battery packs using the above-mentioned five types of holders were disassembled and the inside of the battery pack was examined, the battery pack using the holder 4e was not sufficiently filled with resin, and there was a large hollow portion. It was confirmed that there are a lot of things.

(2) Second Embodiment Next, a battery pack according to a second embodiment of the present invention will be described. In the first embodiment described above, the top cover and the holder are engaged with each other using the top cover locking hole and the hook of the holder, and hot melt resin is injected into the inside from the resin filling hole of the top cover. By doing so, the circuit board is fixed. That is, the terminal depth from the opening surface of the top cover to the contact portion of the circuit board is determined depending on the holding state of the circuit board by the top cover and the holder before the hot melt resin is injected.

  However, if there are deviations in the dimensional tolerances of the locking holes, hooks, and circuit board, the circuit board may be loosened by the holder, so the terminal depth may be deeper than the specified value. Moreover, since it fixes using the hook, it is also considered that the effect which hold | maintains a circuit board with the clearance part of a hook will fade.

  Therefore, in the second embodiment of the present invention, a top cover and a holder that can more securely fix the circuit board are applied. The battery pack according to the second embodiment of the present invention will be schematically described below.

[Positive electrode]
The positive electrode 51 is formed by forming positive electrode active material layers 51a containing a positive electrode active material on both surfaces of a positive electrode current collector 51b. The positive electrode current collector 51b is made of, for example, a metal foil such as an Al foil, a Ni foil, or a stainless steel foil. Since the positive electrode 51 is the same as that of the first embodiment, detailed description thereof is omitted.

[Negative electrode]
The negative electrode 52 is formed by forming negative electrode active material layers 52a containing a negative electrode active material on both surfaces of a negative electrode current collector 52b. The negative electrode current collector 52b is made of metal foil such as copper Cu foil, Ni foil, or stainless steel foil. Since the negative electrode 52 is the same as that of the first embodiment, detailed description thereof is omitted.

[Electrolytes]
As the electrolyte, an electrolyte salt and a non-aqueous solvent that are generally used in lithium ion batteries can be used. Since the electrolyte is the same as that of the first embodiment, detailed description thereof is omitted.

[Separator]
The separator is composed of, for example, a porous film made of a polyolefin-based material such as PP or PE, or a porous film made of an inorganic material such as a ceramic nonwoven fabric, and these two or more kinds of porous films are laminated. It may be a structure. Among these, polyethylene and polypropylene porous films are the most effective. Since the separator is the same as that of the first embodiment, detailed description thereof is omitted.

[Production of battery cells]
The battery element 6 includes a soft laminate film 8a that has been previously drawn into a predetermined shape with a mold for housing the battery element 6, and a hard laminate material 8b that is disposed so as to cover the opening surface of the drawn portion. And enclosed. Then, both ends of the hard laminate material 8b are bent toward the outside of the bottom surface of the drawn portion of the soft laminate film 8a, and are thermally welded to the outside of the bottom surface of the drawn portion. In addition, about the manufacturing process of a battery cell, since it is the same as that of 1st Embodiment, detailed description is abbreviate | omitted.

[Production of battery pack]
The circuit board 30 is fixed to the positive electrode terminal 7a and the negative electrode terminal 7b led out from one (top side) end surface of the battery cell 2 by resistance welding, ultrasonic welding or the like. The circuit board 30 is mounted with a protection circuit including a temperature protection element, an ID resistor for identifying the battery pack, and the like. A plurality of, for example, three contact portions 10 are formed on the circuit board 30. The function of the circuit mounted on the circuit board is the same as that in the first embodiment described above, and a description thereof will be omitted.

  The bottom cover 5 is a resin molded product manufactured by injection molding or the like in a separate process, and is fitted into an opening on the side opposite to one opening of the hard exterior material into which the top cover 20a accommodating the circuit board 30 is fitted. Combined.

  The bottom cover 5 is not limited to this example, and may be molded by directly filling the opening with a hot-melt resin, for example, a polyamide-based resin.

  FIG. 18 is a perspective view showing an appearance of an example of a top cover 20a applicable to the second embodiment of the present invention. The top cover 20a is a resin molded product manufactured by injection molding or the like in a separate process. As shown in FIG. 18, bonding bosses 21a and 21b are formed in the vicinity of both ends of the top cover 20a from the inner side of the upper surface toward the open surface side. The joining bosses 21a and 21b have, for example, a hollow cylindrical shape, and are for joining the top cover 20a and a holder 25a described later. At this time, it is preferable that the outer dimensions of the bonding bosses 21a and 21b be in the range of about φ1 mm to 2 mm, for example.

  Further, side walls 22a and 22b for fitting are formed at both ends of the top cover 20a. Further, locking holes 24a and 24b used for fitting with the holder 25a are provided on the side surface in the longitudinal direction of the top cover 20a.

  FIG. 19 is a perspective view showing an appearance of an example of a holder 25a applicable to the second embodiment of the present invention. The holder 25a is a resin molded product manufactured by injection molding or the like in a separate process. In the vicinity of both ends of the holder 25a, fitting holes 26a and 26b are provided. The fitting holes 26a and 26b allow the joining bosses 21a and 21b of the top cover 20a to pass through when the holder 25a and the top cover 20a are fitted. Further, hooks 27a and 27b used for fitting with the top cover 20a are provided on the side surface in the longitudinal direction of the holder 25a.

  FIG. 20 is a perspective view showing how the top cover 20a and the holder 25a are fitted. Normally, the top cover 20a and the holder 25a are fitted in the state where the electrode terminals 7a and 7b of the battery cell 2 are connected to the circuit board 30, but here, in order to simplify the explanation, the circuit board 30 A description will be given in a state where the electrode terminals 7a and 7b are not connected.

  The circuit board 30 is inserted from the open surface side of the top cover 20a, and further, the holder 25a is fitted from the open surface side of the top cover 20a, so that it is housed between the top cover 20a and the holder 25a.

  When the circuit board 30 is housed between the top cover 20a and the holder 25a, both ends of the circuit board 30 are not in contact with the bosses 21a and 21b. When the top cover 20a and the holder 25a are fitted, both ends of the circuit board 30 are fixed by the holder 25a.

  After the circuit board 30 is accommodated between the top cover 20a and the holder 25a, the top cover 20a and the holder 25a are engaged by mechanical engagement means. That is, when the hook 27a of the holder 25a enters the locking hole 24a of the top cover 20a and the hook 27b enters the locking hole 24b, the top cover 20a and the holder 25a are engaged.

  When the top cover 20a and the holder 25a are fitted, the bosses 21a and 21b provided on the top cover 20a pass through the fitting holes 26a and 26b of the holder 25a as shown in FIG. At this time, it is preferable that the joining bosses 21a and 21b protrude from the bottom surface of the holder 25a by, for example, about 1 mm to 2 mm.

  22 is a cross-sectional view taken along a plane perpendicular to the longitudinal direction, as indicated by a dotted line X-X ′ in FIG. 21. When the top cover 20a and the holder 25a are fitted, as shown in FIG. 22A, the bosses 21a and 21b provided on the top cover 20a pass through the fitting holes 26a and 26b and protrude above the holder 25a. . Then, as shown in FIG. 22B, in a state where the circuit board 30 is fixed so as to be in close contact with the top cover 20a and the holder 25a, the tips of the bosses 21a and 21b are dissolved by, for example, an impulse welder. The top end of the head is substantially hemispherical, and the top cover 20a and the holder 25a are joined. By doing so, the circuit board 30 accommodated between the top cover 20a and the holder 25a is securely fixed.

  Then, similarly to the first embodiment, in order to store the top cover 20a and the holder 25a in the battery cell 2, the fitted top cover 20a and the holder 25a are rotated 90 ° counterclockwise by hand or a jig. Let

  Next, the top cover 20a fitted with the holder 25a is accommodated in the battery cell 2, the full length is held by a jig, and the top cover 20a is thermally welded. That is, a heater block made of a metal such as copper is pressed from above and below near the top cover side end of the exterior material, and the peripheral surface of the top cover 20a and the polypropylene layer on the inner surface of the hard laminate material are thermally welded.

  In this way, the circuit board 30 is fixed so as to be in close contact with the top cover 20a and the holder 25a, and the structure allows the dimensional tolerance of the circuit board 30 and the clearances of the hooks 27a and 27b and the locking holes 24a and 24b to be absorbed. Thus, the terminal depth from the opening surface of the top cover 20a to the contact portion 10 of the circuit board 30 can be made substantially constant.

  Moreover, since the battery cell 2 and the top cover 20a are joined by welding the top cover 20a, the joining strength of the welded portion is high, and the circuit board 30 can be securely fixed without injecting hot melt resin. Can do.

  Furthermore, since the vicinity of both ends of the top cover 20a is welded, even when the top cover 20a is warped, the warp can be suppressed by fitting the top cover 20a and the holder 25a. .

  Next, a first modification of the second embodiment of the present invention will be described. As shown in FIG. 23, a top cover 20b as a first modified example of the second embodiment is used for preventing the disconnection for fixing the top cover 20b to the battery cell 2 on the side walls 22a and 22b for fitting. Protrusions 23a and 23b are provided.

  When the top cover 20b and the holder 25a are fitted and stored in the battery cell 2 as in the second embodiment, as shown in FIG. 24A, the end portion of the top cover 20 and the exterior material of the battery cell 2 are used. There is a difference in the curve shape between the top cover 20b and the protrusions 23a and 23b for preventing the top cover 20 from overlapping with the exterior material before the top cover 20b is fitted. When the top cover 20 is stored in the battery cell 2, the top cover 20 is fixed by press-fitting so that the exterior material of the battery cell 2 is spread as shown in FIG. 24B.

  In this case, it is preferable that the most convex portion of the removal preventing projection 23a and the outer packaging material of the battery cell 2 overlap, for example, about 0.05 mm to 0.1 mm.

  As described above, the top cover 20b and the holder 25a are press-fitted into the battery cell 2 and stored, whereby the bonding strength during storage can be improved.

  Next, a second modification of the second embodiment of the present invention will be described. In the second modification of the second embodiment, when the top cover and the battery cell exterior material are thermally welded, the holder is also thermally welded together with the top cover.

  FIG. 25 shows an appearance of an example of a holder that can be applied to the second modification of the second embodiment. Welded portions 28a, 28b, 28c and 28d are provided on the side surface of the holder 25b. When the top cover 20a and the holder 25b are fitted, the side surfaces of the top cover 20a and the welded portions 28a, 28b, 28c of the holder 25b are provided. And 28d are formed to have substantially the same height. Although a fitting hole 26a is provided on the left hand side of the holder 25b, it is not shown in FIG.

  FIG. 26 is a cross-sectional view of the fitting hole 26a when the top cover 20a and the holder 25b are stored in the battery cell 2 when the holder 25b is used. When the fitted top cover 20a and holder 25b are housed in the battery cell 2, the side surface of the top cover 20a contacts the exterior material of the battery cell 2, and the welded portion of the holder 25b is as shown by the dotted circle. 28a, 28b, 28c and 28d are in contact with the exterior material. And by performing heat welding similarly to the above-mentioned 2nd Embodiment, while the top cover 20a is heat-welded, the welding parts 28a, 28b, 28c, and 28d of the holder 25b are heat-welded.

  Thus, by thermally welding the top cover 20a and the holder 25b to the outer packaging material of the battery cell 2, it is possible to improve the bonding strength with the outer packaging material and to suppress deformation on the top cover side during dropping. .

(3) Third Embodiment Next, a battery pack according to a third embodiment of the invention will be described. In the third embodiment, the top cover and the holder according to the second embodiment described above are used for battery cells with higher sealing performance.

  FIG. 27 shows the external appearance of a battery pack 40 according to the third embodiment of the present invention. In this battery pack 40, a power generation element is housed in a hard laminate film 41 as an exterior material, and a top cover 20a and a bottom cover 43, which are resin molded covers, are fitted to both ends of the opening, and products are produced as necessary. A label 46 is provided. In FIG. 27, parts common to the first and second embodiments described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 28 shows an exemplary configuration of the battery cell 45 according to the third embodiment of the present invention. The battery pack 40 includes a power generation element 50 whose battery elements are covered with a soft laminate film, a circuit board 30, a top cover 20a, and a bottom cover 43. The power generation element 50 is covered with a hard laminate film 41. It is a battery cell.

  The top cover 20a 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 opening of the battery cell. The top cover 20a is further fitted with a holder 25a, and the circuit board 30 is disposed between the top cover 20a and the holder 25a. The bottom cover 43 is a resin molded cover that is provided at the bottom of the battery and fitted into the opening of the battery cell 45. The top cover 20a and the bottom cover 43 are bonded to the battery cell 45 by thermal welding or the like after being fitted into the opening of the battery cell 45.

  The circuit board 30 has a protective circuit mounted in advance, and the positive terminal and the negative terminal derived from the power generation element 50 and the protective 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 30 can be the same as that in the first and second embodiments described above, and thus detailed description thereof is omitted.

  Hereinafter, the configuration of the battery pack 40 will be described.

[Positive electrode]
The positive electrode 51 is formed by forming positive electrode active material layers 51a containing a positive electrode active material on both surfaces of a positive electrode current collector 51b. The positive electrode current collector 51b is made of, for example, a metal foil such as an Al foil, a Ni foil, or a stainless steel foil. Since the positive electrode 51 is the same as that of the first embodiment, detailed description thereof is omitted.

[Negative electrode]
The negative electrode 52 is formed by forming negative electrode active material layers 52a containing a negative electrode active material on both surfaces of a negative electrode current collector 52b. The negative electrode current collector 52b is made of metal foil such as copper Cu foil, Ni foil, or stainless steel foil. Since the negative electrode 52 is the same as that of the first embodiment, detailed description thereof is omitted.

[Electrolytes]
As the electrolyte, an electrolyte salt and a non-aqueous solvent that are generally used in lithium ion batteries can be used. Since the electrolyte is the same as that of the first embodiment, detailed description thereof is omitted.

[Separator]
The separator is composed of, for example, a porous film made of a polyolefin-based material such as PP or PE, or a porous film made of an inorganic material such as a ceramic nonwoven fabric, and these two or more kinds of porous films are laminated. It may be a structure. Among these, polyethylene and polypropylene porous films are the most effective. Since the separator is the same as that of the first embodiment, detailed description thereof is omitted.

[Production of power generation elements]
The battery element 6 produced in the same manner as in the first embodiment described above is packaged with a soft laminate film 8a and molded to produce a power generation element 50 as shown in FIG.

  The soft laminate film 8a is formed of a multilayer film having moisture resistance and insulation, in which a metal foil indicated by reference numeral 61 is sandwiched between an exterior layer 62 and a sealant layer 63. In addition, since the laminated film of the structure shown in FIG. 5 can be used for the soft laminated film 8a similarly to 1st Embodiment, detailed description is abbreviate | omitted.

  As shown in FIG. 30, the soft laminate film 8a has a concave portion 57a formed by deep drawing, and after the battery element 6 is accommodated in the concave portion 57a, the soft laminate film 8a is folded back so that the soft laminate film 8a is an opening of the concave portion 57a. To cover. Next, the power generation element 50 is formed by sealing the three sides of the battery element 6 except 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 50 may delete unnecessary portions of the top portion, which are the lead-out sides of the positive electrode terminal 7a and the negative electrode terminal 7b, by trimming in consideration of a later manufacturing process. As shown in FIGS. 31A and 31B, by performing trimming along the line of reference symbol P, for example, interference between the top cover and the soft laminate film can be reduced.

[Production of battery cells]
The power generation element 50 thus produced is covered with a hard laminate film 41 to produce a battery cell 45. First, the configuration of the hard laminate film 41 will be described.

  As shown in FIG. 32, the hard laminate film 41 has a metal foil indicated by reference numeral 71 sandwiched between an exterior layer 72 made of a resin film and a sealant layer 73 made of a resin film. It consists of a multilayer film having an adhesive layer 74 and having moisture resistance and insulation properties.

  The metal layer 71 is made of a hard metal material, and aluminum, stainless steel, copper, titanium, tin plate, 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. Further, the metal layer 71 and the exterior layer 72, and the metal layer 71 and the sealant layer 73 are bonded together via adhesive layers 75 and 76. The adhesive layer 75 may be omitted as necessary.

  For the exterior layer 72, a polyolefin resin, a polyamide resin, a polyimide resin, a polyester, or the like is used because of its 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 sealant layer 73 is a portion that is melted by heat or ultrasonic waves and welded to each other. In addition to polyethylene (PE), non-axially oriented polypropylene (CPP), polyethylene terephthalate (PET), 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 thermal adhesive layer 74 is for adhering the power generating element 50 and the hard laminate film 41 covered with the soft laminate film 8a without separately providing an adhesive member. As the thermal adhesive layer 74, a resin material having excellent adhesiveness with Ny, PET, PEN and the like used as an exterior layer of the soft laminate film 8a and having a melting temperature that does not affect the battery element is used. The thermal adhesive layer 74 uses a resin material having a lower melting point than the material used for the sealant layer 73.

  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 resins, polyester resins, and ionomers can be used, and a plurality of types can be selected and used. The heat bonding layer 74 is a method of bonding these materials in a film form, a method of applying and cooling a resin material (hot melt resin) melted by heat, diluting the hot melt resin with a solvent, and drying the solvent after application. Or the like can be used.

  In such a hard laminate film 41, the thermal bonding layer 74 is provided with a thickness of about 1 to 5 μm. Moreover, since the metal layer 71 has a function of using the outermost package of the battery pack 40 to maintain the strength of the battery pack 40, the metal layer 71 is used with a thickness of about 50 to 100 μm. The exterior layer 72 is used in a thickness of about 9 to 15 μm, and the sealant layer 73 is used in a thickness of about 25 to 35 μm.

  The sealant layer 73 is used as a welding layer when the top cover 20 and the bomb cover 43 are thermally welded later. For this reason, a resin material having good adhesion to the top cover 20a and the bottom cover 43 is selected. The sealant layer 73 also has a cushion function when the hard laminate film 41 is bonded to the power generation element 50. That is, when the soft laminate film 8a, which is an exterior material of the power generation element 50, and the hard laminate film 41 are thermally welded via the thermal adhesive layer 74, each laminate film has fine irregularities on the surface. In some cases, the adhesiveness is not excellent. By providing the sealant layer 73 having a thickness of about 25 to 35 μm, the sealant layer 73 serves as a cushion, and the laminate films having fine irregularities on the surface can be favorably bonded to each other.

  The exterior material made of such a hard laminate film 41 is bonded to the power generation element 50. First, as shown in FIG. 33A, the hard laminate film 41 is bent so as to wrap the power generation element 50, and is packaged so that the end of the hard laminate film 41 is aligned with the upper surface of the power generation element 50. Next, a heater block is applied from the upper surface and the bottom surface of the power generation element 50 and heated while being pressurized at a temperature at which the resin material of the thermal bonding layer 74 is melted. The resin material of the heat bonding layer 74 is melted to become an adhesive, and bonds the hard laminate film 41 and the power generation element 50. Thereby, the battery cell 45 whose cross section is shown in FIG. 33B is manufactured.

  Although the temperature of the heater block varies depending on the resin material of the thermal bonding layer 74, the temperature is higher than the melting temperature of the resin material of the thermal bonding layer 74 and lower than the melting temperature of the resin material used for the sealant layer 73. Thereby, only the resin material of the heat bonding layer 74 can be melted and bonded without melting the resin material of the sealant layer 73.

  Further, when the heating temperature exceeds 120 ° C., it is considered that the battery element 6 is affected. For example, the separators 53a and 53b used in the battery element 6 are often made of polyethylene (PE), but since the melting point of PE is about 120 ° C., it is considered that the safety and the battery function are lowered. Thus, the heater block is heated to an upper limit of about 110 ° C.

  The hard laminate film 41 is not limited to the configuration shown in FIG. 33 but may be configured as shown in FIGS.

  34A and 34B are configurations in which the hard laminate film 41 is provided so as to cover the bottom surface portion of the power generation element 50 to form the battery cell 45, and a joint line of the hard laminate film 41 is provided on the upper surface portion of the battery cell 45. It is done. Note that the battery cell of FIG. 33 is shaped so that the side portions are rounded, whereas the battery cell of FIG. 34 has a substantially rectangular cross section.

  35A and 35B show a configuration in which the hard laminate film 41 is provided so as to cover one side portion of the power generation element 50 to form a battery cell 45, and the hard laminate film 41 is formed on one side portion of the battery cell 45. A seam is provided.

  36A and 36B show a configuration in which two hard laminate films 41 are provided so as to cover both side portions of the power generation element 50 to form a battery cell 45. Hard laminates are formed on the upper surface portion and the bottom surface portion of the battery cell 45. A seam of the film 41 is provided.

  37A and 37B show a configuration in which two hard laminate films 41 are provided so as to cover the upper surface portion and the bottom surface portion of the power generation element 50 to form a battery cell 45, and are hard on both side portions of the battery cell 45. A seam of the laminate film 41 is provided.

[Production of battery pack]
Next, the circuit board 30 is connected to the positive terminal 7a and the negative terminal 7b. The positive terminal 7a and the negative terminal 7b led out from the top part of the battery cell 45 molded into a predetermined shape and the protection circuit mounted in advance on the circuit board 30 are fixed by resistance welding, ultrasonic welding, or the like. The circuit board 30 connected to the battery cell 45 is inserted between a pre-molded top cover 20a and holder 25a. Since the top cover 20a and the holder 25a are the same as those shown in FIGS. 18 and 19, detailed description thereof is omitted.

  The top cover 20a is a resin molded product manufactured by injection molding or the like in a separate process. Bonding bosses 21a and 21b are formed in the vicinity of both ends of the top cover 20a. Further, side walls 22a and 22b for fitting are formed at both ends of the top cover 20a. Further, locking holes 24a and 24b used for fitting with the holder 25a are provided on the side surface in the longitudinal direction of the top cover 20a.

  The holder 25a is a resin molded product manufactured by injection molding or the like in a separate process. In the vicinity of both ends of the holder 25a, fitting holes 26a and 26b are provided. Further, hooks 27a and 27b used for fitting with the top cover 20a are provided on the side surface in the longitudinal direction of the holder 25a.

  Next, a method for fitting the top cover 20a and the holder 25a will be schematically described. In addition, since the fitting method of the top cover 20a and the holder 25a is the same as that of what is shown in FIGS. 20-22, detailed description is abbreviate | omitted.

  The circuit board 30 is inserted from the open surface side of the top cover 20a, and further, the holder 25a is fitted from the open surface side of the top cover 20a, so that it is housed between the top cover 20a and the holder 25a.

  After the circuit board 30 is stored between the top cover 20a and the holder 25a, the hook 27a of the holder 25a enters the top cover 20a into the locking hole 24a, and the hook 27b enters the locking hole 24b. By entering, the top cover 20a and the holder 25a are engaged.

  Further, when the top cover 20a and the holder 25a are engaged, the bosses 21a and 21b provided on the top cover 20a pass through the fitting holes 26a and 26b of the holder 25a, and protrude above the holder 25a. In a state where the circuit board 30 is fixed so as to be in close contact with the top cover 20a and the holder 25a, the tips of the bosses 21a and 21b are substantially hemispherical by, for example, dissolving the tips of the bosses 21a and 21b with an impulse welder. The top cover 20a and the holder 25a are joined, and the circuit board 30 accommodated between the top cover 20a and the holder 25a is securely fixed.

  Then, similarly to the first embodiment, in order to store the top cover 20a and the holder 25a in the battery cell 2, the fitted top cover 20a and the holder 25a are rotated 90 ° counterclockwise by hand or a jig. Then, the top cover 20a fitted with the holder 25a is fitted into the opening of the top part of the battery cell 45 so that the positive electrode terminal 7a and the negative electrode terminal 7b are bent in the battery cell 45.

  Next, the fitting portion between the top cover 20a and the battery cell 45 is heated by the heater head, and the top cover 20a and the battery cell 45 are thermally welded. At this time, the temperature of the heater head is higher than that at the time of battery cell formation, and is equal to or higher than the melting temperature of the resin material of the sealant layer 73, and the top cover 20 a is bonded to the sealant layer 73 instead of the heat bonding layer 74.

  The heat bonding layer 74 heated when the hard laminate film 41 and the power generation element 50 are bonded is pressed by the top cover 20a when the top cover 20a is fitted, and moves to the back of the battery cell 45. As described above, since a resin material having a lower melting temperature than that of the sealant layer 73 is used for the thermal adhesive layer 74, only the thermal adhesive layer 74 is bonded to the hard laminate film 41 and the power generation element 50. Will melt. For this reason, the thermal adhesive layer 74 can be moved without moving the sealant layer 73 used for bonding to the top cover 20a, and the sealant layer 73 can be exposed.

  Subsequently, the bottom cover 43 is fitted to the bottom part of the battery cell 45, and the fitting part between the bottom cover 43 and the battery cell 45 is heated by the heater head to thermally weld the bottom cover 43 and the battery cell 45. Also in this case, as in the case of the top cover 20a, when the bottom cover 43 is fitted, the thermal adhesive layer 74 is pushed by the bottom cover 43 and moves to the back of the battery cell 45, and the exposed sealant layer 73 and the bottom cover are exposed. 43 is bonded.

  At this time, an adhesive or hot melt resin may be injected into the gap between the power generation element 50 and the bottom cover 43 as necessary. In this case, an adhesive / hot melt resin inlet is provided in the bottom cover 43 in advance. Further, the fitting of the top cover 20a and the bottom cover 43 and the heat welding process may be performed simultaneously.

  Further, the bottom cover 43 not only uses a pre-molded member, but also uses a method of molding the battery cell 45 integrally with the battery cell 45 by placing the battery cell 45 in a mold and pouring hot melt resin into the bottom part. Is also possible.

  As described above, a resin material having good adhesiveness with the top cover 20 a and the bottom cover 43 is provided as the sealant layer 73 on the inner side of the metal layer 71, and the outer layer 62 of the hard laminate film 41 is adhesive with the inner side of the sealant layer 73. The heat generating element 50, the hard laminate film 41, the battery cell 45, the top cover 20a, and the bottom cover 43 can be made better by providing the heat bonding layer 74 using a resin material having a melting temperature higher than that of the sealant layer 73. Can be glued. For this reason, it becomes the battery pack 40 structure which is hard to be damaged.

  Although the embodiment of the present invention has been specifically described above, the present invention is not limited to the above-described first, second and third embodiments of the present invention, and does not depart from the gist of the present invention. Various modifications and applications are possible within the range.

It is a perspective view which shows the structure of an example of the battery pack in 1st Embodiment of this invention. It is a perspective view which shows the structure of an example of the battery element in 1st Embodiment of this invention. It is an expanded view which shows an example of the shape of the exterior material which coat | covers the battery element in 1st Embodiment of this invention. It is a perspective view which shows an example of the external appearance of the battery element coat | covered with the exterior material in 1st Embodiment of this invention. It is sectional drawing which shows the structure of the soft laminate film by 1st Embodiment of this invention. In 1st Embodiment of this invention, it is a perspective view which shows the state by which the circuit board was connected to the battery cell. In 1st Embodiment of this invention, it is a perspective view which shows a mode that a top cover is attached to a battery cell. It is a perspective view which shows the 1st example of the holder in 1st Embodiment of this invention. In 1st Embodiment of this invention, it is a perspective view which shows a mode that a top cover and a holder are fitted. It is a perspective view which shows the detail of the fitting part of the top cover and holder in 1st Embodiment of this invention. In 1st Embodiment of this invention, it is a perspective view which shows a mode that a top cover and a holder are inserted in opening of the end surface of a battery cell. It is a perspective view which shows the 2nd example of the holder in 1st Embodiment of this invention. It is a perspective view which shows the 3rd example of the holder in 1st Embodiment of this invention. In 1st Embodiment of this invention, it is the enlarged view which looked at the resin filling hole vicinity at the time of engaging a top cover and a holder from the holder side. It is a perspective view which shows an example of the shape of the holder at the time of providing multiple board | substrate support protrusions. It is a perspective view which shows an example of the shape of a holder. It is a perspective view which shows an example of the shape of the holder used for the conventional battery pack. It is a perspective view which shows the external appearance of an example of the top cover applicable to 2nd Embodiment of this invention. It is a perspective view which shows the external appearance of an example of the holder applicable to 2nd Embodiment of this invention. It is a perspective view which shows a mode that the top cover applicable to 2nd Embodiment of this invention and a holder are fitted. It is a perspective view which shows the state by which the top cover applicable to 2nd Embodiment of this invention and the holder were fitted. It is sectional drawing at the time of cut | disconnecting the boss vicinity in the state with which the top cover applicable to 2nd Embodiment of this invention and the holder were fitted by the surface perpendicular | vertical with respect to a longitudinal direction. It is a perspective view which shows an example of the external appearance of the top cover applicable to the 1st modification of the 2nd Embodiment of this invention. It is a basic diagram which shows the edge part of the battery cell at the time of a fitting, and a top cover. It is a perspective view which shows the external appearance of an example of the holder applicable to the 2nd modification of the 2nd Embodiment of this invention. It is sectional drawing at the time of storing a top cover and a holder in a battery cell in the case of using the holder applicable to the 2nd modification of the 2nd Embodiment of this invention. It is a basic diagram which shows the structure of an example of the battery pack by 3rd Embodiment of this invention. It is a basic diagram which shows the structure of an example of the battery pack by 3rd Embodiment of this invention. It is a basic diagram which shows the structure of an example of the electric power generation element by 3rd Embodiment of this invention. It is a basic diagram which shows the structure of an example of the electric power generation element by 3rd Embodiment of this invention. It is a basic diagram which shows the structure of an example of the electric power generation element by 3rd Embodiment of this invention. It is a basic diagram which shows the structure of the hard laminate film by 3rd Embodiment of this invention. It is a basic diagram which shows the structure of an example of the battery cell by the 3rd Embodiment of this invention. It is a basic diagram which shows the structure of an example of the battery cell by the 3rd Embodiment of this invention. It is a basic diagram which shows the structure of an example of the battery cell by the 3rd Embodiment of this invention. It is a basic diagram which shows the structure of an example of the battery cell by the 3rd Embodiment of this invention. It is a basic diagram which shows the structure of an example of the battery cell by the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 40 Battery pack 2, 45 Battery cell 3, 20a, 20b Top cover 4, 4a, 4b, 4c, 4d, 4e, 25a, 25b Holder 5 Bottom cover 6 Battery element 7a Positive electrode terminal 7b Negative electrode terminal 9, 30 Circuit board 12a Resin filling hole 12b Degassing holes 13a, 13b, 13b 'Protrusions 14a, 14b, 14b', 14c Substrate support protrusions 17a, 17b Extension parts 21a, 21b Bonding bosses 23a, 23b Protrusion prevention protrusions 28a, 28b, 28c , 28d welding part 50 power generation element

Claims (9)

In a battery pack having a battery element of a secondary battery,
The battery element is housed in a hard exterior having first and second openings at both ends,
A first cover is provided in the first opening;
A second cover is provided in the second opening;
The battery element lead and the circuit board are joined together,
The first cover includes a top cover and a holder that are fitted by mechanical engagement means,
The circuit board is housed between the top cover and the holder,
The top cover has a resin filling hole for filling the space between the battery element and the first cover with resin,
The holder has protrusions at both ends, a notch is provided at the center of the protrusion, and one or more substrate support protrusions protruding toward the circuit board are formed near the center.
A battery pack, wherein a space between the battery element and the first cover is filled with resin. The battery pack according to claim 1,
The substrate support protrusion further has a surface parallel to the longitudinal direction. The battery pack according to claim 1,
The substrate support protrusion has a surface orthogonal to the longitudinal direction, and the tip of the surface has a tapered trapezoidal shape. The battery pack according to claim 1,
The battery pack is characterized in that the holder is formed with extending portions in the longitudinal direction from the protrusions at both ends. In a battery pack having a battery element of a secondary battery,
The battery element is housed in a hard exterior having first and second openings at both ends,
A first cover is provided in the first opening;
A second cover is provided in the second opening;
The battery element lead and the circuit board are joined together,
The first cover includes a top cover and a holder,
The circuit board is housed between the top cover and the holder,
The top cover has a boss and a locking hole for coupling with the holder, the bosses are formed at both ends on the circuit board side, and the locking holes are provided on both side surfaces of the top cover. And
The holder has holes for passing the bosses are formed at both ends Rutotomoni, on both sides of the holder, the hook used at the time of fitting between the top cover is provided respectively,
After the circuit board is stored between the top cover and the holder, the top cover and the holder are engaged by the hook of the holder entering the locking hole of the top cover,
The boss of the top cover penetrates into the hole of the holder, by Rukoto dissolve the tip of the boss, the battery pack, characterized in that the said top cover and the holder are joined. In a battery pack having a battery element of a secondary battery,
The battery element is housed in a hard exterior having first and second openings at both ends,
A first cover is provided in the first opening;
A second cover is provided in the second opening;
The battery element lead and the circuit board are joined together,
The first cover includes a top cover and a holder,
The circuit board is housed between the top cover and the holder,
Boss is formed at both ends of the top cover,
The holder is formed with holes for penetrating the boss at both ends,
The boss of the top cover penetrates into the hole of the holder, by Rukoto dissolve the tip of the boss, the battery pack, characterized in that the said top cover and the holder are joined. The battery pack according to claim 5 or 6 ,
The top cover has a protrusion for preventing the first cover from being pulled out to fix the first cover to the first opening;
The battery pack is characterized in that the first cover is fitted so that the hard exterior is pushed and spread by the protrusions for preventing removal. The battery pack according to claim 5 or 6 ,
The battery pack according to claim 1, wherein the holder has a welded portion for fixing the first cover to the first opening. The battery pack according to claim 5 or 6,
The peripheral surface of the top cover and the inner surface of the exterior are heat welded.
A battery pack characterized by that.

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