JP2006351245A - Battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery pack capable of efficiently cooling secondary batteries. <P>SOLUTION: The battery pack 30 is provided with a plurality of battery modules 20 housing a laminated body laminating a plurality of thin secondary batteries 10 in a case 22, ducts 32, 33 and a fan 34 for supplying cooling air for cooling the thin batteries 10 with. The plurality of battery modules 20 are arrayed and laminated, with a guide-in port 23h for guiding in cooling air inside the case 22 and an exhaust port 23i for exhausting the cooling air guided into the case 22 through the guide-in port 23h provided at side face parts of the case 22. A partitioning member 35 for blocking a gap between the guide-in port 23h and the exhaust port 23i is further provided between the battery modules 20. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an assembled battery configured by stacking a plurality of thin secondary batteries using sheet-like members as exterior members and electrically connecting them.

  The electrode plate laminated via the separator is housed and sealed in a sheet-like member as an exterior member, and the electrode terminal connected to the electrode plate is led out from the outer peripheral edge of the sheet-like member. A battery is conventionally known (see, for example, Patent Document 1). In addition, in order to secure a desired capacity and voltage, a technique is known in which a plurality of such thin secondary batteries are stacked and electrically connected and housed in a case to constitute a battery module ( For example, see Patent Document 2).

  Further, it is considered that a plurality of such battery modules are arranged and battery modules are connected to form an assembled battery and used as a power source for an electric vehicle or a hybrid vehicle.

In such an assembled battery, extra space is eliminated as much as possible in order to reduce the size and weight, but each secondary battery generates heat as it is released and charged, so that limited space is effectively used. Thus, it is necessary to cool each secondary battery efficiently.
Japanese Patent Laid-Open No. 9-259859 JP 2001-256934 A

An object of this invention is to provide the assembled battery which can cool a secondary battery efficiently.
In order to achieve the above object, according to the present invention, an electrode plate laminated via a separator is accommodated and sealed in an exterior member, and an electrode terminal connected to the electrode plate is disposed outside the exterior member. A plurality of secondary batteries derived from the periphery, a plurality of battery modules in which the stack is accommodated in a case, and a refrigerant supply means for supplying a refrigerant for cooling the secondary battery, The battery modules are arranged side by side and stacked, and at least one surface of the case is provided with an inlet for introducing the refrigerant supplied from the refrigerant supply means into the case, and through the inlet A discharge port for discharging the refrigerant introduced into the case, and between the battery modules, the introduction port formed on at least one surface of the case and the front Further comprising battery pack partition means dam between the outlet port is provided.

  In the present invention, in an assembled battery including a plurality of battery modules in which a plurality of secondary batteries are stacked and accommodated in a case, an introduction port and a discharge port are provided on at least one surface of the case, and the gap between them is blocked. A partition means is provided between the battery modules. As a result, the refrigerant supplied from the refrigerant supply means can be actively taken into the case through the inlet, so that the secondary battery constituting the battery module can be efficiently cooled. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a plan view showing an entire thin battery according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a secondary battery taken along line II-II in FIG. 1 and 2 show one thin battery 10 (unit battery), and a plurality of thin batteries 10 are stacked and electrically connected to form an assembled battery having a desired voltage and capacity.

  First, a thin battery 10 according to an embodiment of the present invention is a lithium-based thin secondary battery. As shown in FIGS. 1 and 2, the thin battery 10 includes three positive plates 101, five separators 102, three negative plates 103, a positive terminal 104, a negative terminal 105, and an upper portion. It is comprised from the exterior member 106, the lower exterior member 107, and the electrolyte which is not specifically illustrated, for example, has a total thickness of 10 mm or less. In the present embodiment, the positive electrode plate 101, the separator 102, the negative electrode plate 103, and the electrolyte are particularly referred to as a power generation element 108.

  As shown in FIG. 2, the positive electrode plate 101 of the power generation element 108 is formed on each of the main surfaces of the positive electrode current collector 101a extending to the positive electrode terminal 104 and a part of the positive electrode current collector 101a. Positive electrode layers 101b and 101c.

  The positive electrode side current collector 101a is made of an electrochemically stable metal foil such as an aluminum foil, an aluminum alloy foil, a copper foil, or a nickel foil.

The positive electrode layers 101b and 101c are formed by mixing a positive electrode active material, a conductive agent such as carbon black, and an adhesive such as an aqueous dispersion of polytetrafluoroethylene with a part of the positive electrode side current collector 101a. It is formed by applying to both main surfaces, drying and rolling. Examples of the positive electrode active material include lithium composite oxides such as lithium nickelate (LiNiO ₂ ), lithium manganate (LiMnO ₂ ), and lithium cobaltate (LiCoO ₂ ), and chalcogen (S, Se, Te) compounds. Etc. can be mentioned.

  The negative electrode plate 103 of the power generation element 108 includes a negative electrode side current collector 103a extending to the negative electrode terminal 105, and negative electrode layers 103b and 103c formed respectively on both main surfaces of the negative electrode side current collector 103a, have.

  The negative electrode side current collector 103a is made of an electrochemically stable metal foil such as a nickel foil, a copper foil, a stainless steel foil, or an iron foil.

  The negative electrode layers 103b and 103c are prepared by mixing an aqueous dispersion of a styrene butadiene rubber resin powder as a precursor material of an organic fired body into the negative electrode active material that absorbs and releases lithium ions of the positive electrode active material, and then drying it. By pulverizing, the main material is carbonized styrene butadiene rubber supported on the surface of the carbon particles, and a binder such as an acrylic resin emulsion is further mixed therewith, and this mixture is mixed with one of the negative electrode side current collector 103a. It is formed by applying to both main surfaces of the part, drying and rolling. Examples of the negative electrode active material include amorphous carbon, non-graphitizable carbon, graphitizable carbon, and graphite.

  In particular, when amorphous carbon or non-graphitizable carbon is used as the negative electrode active material, the flatness of the potential during charge / discharge is poor and the output voltage decreases with the amount of discharge. Although unsuitable, it is advantageous because there is no sudden drop in output used as a power source for electric vehicles.

  The separator 102 of the power generation element 108 prevents a short circuit between the positive electrode plate 101 and the negative electrode plate 103 and may have a function of holding an electrolyte. The separator 102 is a microporous film made of polyolefin such as polyethylene (PE) or polypropylene (PP), for example, and when an overcurrent flows, the pores of the layer are blocked by the heat generation, thereby blocking the current. It also has a function.

  In addition, the separator in the present invention is not limited to a single layer film such as polyolefin, but a three-layer structure in which a polypropylene film is sandwiched with a polyethylene film, or a laminate of a polyolefin microporous film and an organic nonwoven fabric may be used. I can do it. Thus, by forming the separator in multiple layers, various functions such as an overcurrent prevention function, an electrolyte holding function, and a separator shape maintenance (stiffness improvement) function can be provided.

  In the power generation element 108 described above, the positive electrode plates 101 and the negative electrode plates 103 are alternately stacked via the separators 102. The three positive plates 101 are respectively connected to the positive terminal 104 made of metal foil via the positive current collector 101a, while the three negative plates 103 are connected to the negative current collector 103a. In the same manner, each is connected to a negative electrode terminal 105 made of metal foil.

  The positive electrode plate 101, the separator 102, and the negative electrode plate 103 of the power generation element 108 are not limited to the above number in the present invention. For example, one positive plate, three separators, one negative plate However, the power generation element can be configured, and the number of positive plates, separators, and negative plates can be selected and configured as necessary.

  The positive electrode terminal 104 and the negative electrode terminal 105 are not particularly limited as long as they are electrochemically stable metal materials. Examples of the positive electrode terminal 104 include, for example, an aluminum foil and an aluminum alloy, similar to the positive electrode side current collector 101a described above. A foil, copper foil, nickel foil, etc. can be mentioned. Moreover, as the negative electrode terminal 105, nickel foil, copper foil, stainless steel foil, iron foil, etc. can be mentioned similarly to the above-mentioned negative electrode side collector 103a, for example. In the present embodiment, the metal foils constituting the current collectors 101 a and 103 a of the electrode plates 101 and 103 are extended to the electrode terminals 104 and 105, so that the electrode plates 101 and 103 are directly connected to the electrode terminals 104 and 105. Although connected, the current collectors 101a and 103a of the electrode plates 101 and 103 and the electrode terminals 104 and 105 are connected by a material or component different from the metal foil constituting the current collectors 101a and 103a. Also good.

  The power generation element 108 is accommodated and sealed between an upper exterior member 106 molded into a cup shape as shown in FIG. 2 and a flat lower exterior member 107. Both the upper exterior member 106 and the lower exterior member 107 in the present embodiment are configured by a sheet-like member including an inner resin layer, a metal layer, and an outer resin layer, although not particularly illustrated.

  The inner resin layer of this sheet-like member is made of a resin film excellent in electrolytic solution resistance and heat fusion properties, such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, or ionomer. The metal layer is made of a metal foil such as aluminum. The outer resin layer is made of, for example, a resin film excellent in electrical insulation, such as a polyamide resin or a polyester resin.

  In order to maintain the sealing performance inside the thin battery 10, a seal film made of, for example, polyethylene or polypropylene is interposed between the electrode terminals 104 and 105 and the exterior members 106 and 107. Also good. It is preferable from the viewpoint of heat-fusibility that the seal film is made of the same system as the synthetic resin material constituting the inner resin layer of the exterior members 106 and 107 in both the positive electrode terminal 104 and the negative electrode terminal 105. .

  These exterior members 106 and 107 enclose part of the power generation element 108 and the electrode terminals 104 and 105 described above, and in the space formed by the exterior members 106 and 107, lithium perchlorate or borofluoride is added to the organic liquid solvent. While injecting a liquid electrolyte having a lithium salt such as lithium or lithium hexafluorophosphate as a solute, the space is evacuated, and the outer peripheral edges of the exterior members 106 and 107 are heat-sealed by hot pressing. As a result, the power generation element 108 and part of the electrode terminals 104 and 105 are accommodated in the exterior members 106 and 107 and sealed.

  Examples of the organic liquid solvent include ester solvents such as propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), and methyl ethyl carbonate. The organic liquid solvent of the present invention is not limited to this, and an organic liquid solvent prepared by mixing and preparing an ether solvent such as γ-butylactone (γ-BL) or dietoshietane (DEE) in an ester solvent. It can also be used.

  Below, the assembled battery 30 comprised by connecting two or more above-mentioned thin batteries 10 is demonstrated.

  3 is an overall perspective view of the assembled battery according to the embodiment of the present invention, FIG. 4 is a sectional view showing the arrangement of the battery modules constituting the assembled battery shown in FIG. 3, and FIG. 5 is a sectional view taken along line VV in FIG. 6 is an enlarged cross-sectional view of the VI part of FIG. 5, FIG. 7 is an enlarged cross-sectional view of the VII part of FIG. 4, FIG. 8 is a perspective view showing the battery module in the embodiment of the present invention, and FIG. It is the disassembled perspective view which flips the assembled battery shown upside down, and shows it further disassembled.

  As shown in FIGS. 3 to 5, the assembled battery 30 according to the embodiment of the present invention includes a plurality of battery modules 20 configured by using a plurality of the thin batteries 10 described above, and the plurality of battery modules 20 arranged side by side. A container 31 housed in the internal space 31a in a state of being disposed and stacked; an inlet-side duct 32 that communicates the outside of the assembled battery 30 and the internal space 31a of the container 31 via the inlet-side opening 31b of the container 31; 31 between the internal space 31a of 31 and the outside of the assembled battery 20 through the outlet side opening 31c of the container 31, the fan 34 disposed in the outlet side duct 33, and the battery modules 20 And a partition member 35 provided therebetween.

  In the battery module 20 of the assembled battery 30, as shown in FIG. 9, a battery stack is formed by stacking eight thin batteries 10 in such a posture that the electrode terminals 104 and 105 are led out in substantially the same direction. 21 is configured. The battery stack 21 is housed inside a hollow case 22.

  As shown in FIGS. 8 and 9, the case 22 is composed of a lower case 23 having a box shape with one surface opened, and an upper case 24 forming a lid for closing the opening. The edge portion 24a of the upper case 24 is wound around the edge portion 23b of the side surface portion 23a of the lower case 23 by caulking (see a partially enlarged sectional view of FIG. 8). The lower case 23 and the upper case 24 are composed of a plate material made of a material having excellent heat transfer properties such as a relatively thin aluminum plate or steel plate, and are given a predetermined shape by pressing.

  The eight thin batteries 10 constituting the electrode laminate 21 are connected in series or in parallel, such that the electrode terminals 104 and 105 are directly connected to each other in the spacer portion 25a or are connected via a bus bar (not shown). As a result, the thin batteries 10 are electrically connected to the positive electrode output terminal 25f and the negative electrode output terminal 25g.

  The positive terminal 25 f is led out from the case 22 through a first notch 23 d formed in a part of the side surface portion 23 a of the lower case 23. Similarly, the negative output terminal 25g is also led out from the case 22 through a second notch 23e formed in a part of the side surface portion 23a of the lower case 23. A third cutout 23f is formed in a part of the side surface portion 23a of the lower case 23, and the female connector 25c is led out from the case 22 through the third cutout 23f. Although not particularly shown, the female connector 27 is connected to the electrode terminals 104 and 105 of each thin battery 10 at the spacer portion 25a, and a male connector (not shown) is inserted into the female connector 25c. When a voltage detector (not shown) connected to the male connector detects the voltage of each thin battery 10, charge / discharge management of the battery module 20 can be performed. An insulating cover 25b is interposed between the positive electrode output terminal 25f, the female side connector 25c, and the negative electrode side output terminal 25g in order to maintain insulation.

  In order to allow bolts (not shown) to pass through the four corners of the case 22, through holes 23g are formed in the four corners of the lower case 23, and also in the four corners of the upper case 24. A through hole 24b is formed. In addition, through holes 25a1 through which the sleeve 25d is inserted are also formed at two positions on both ends of each spacer portion 25.

  When the battery modules 20 are stacked to form the assembled battery 30, the stacked battery modules 20 are fixed by inserting bolts into the through holes 23 g and 24 b of the case 22 and the sleeve 28. The

  Furthermore, in this embodiment, as shown in FIGS. 8 and 9, an introduction port 23 h is formed at one end of the long side portion 23 a 1 of the side surface portion 23 a of the lower case 23. A discharge port 23i is formed at the other end of the long side portion 23a1. The opening shapes of the introduction port 23h and the discharge port 23i may be, for example, a circle or an ellipse in addition to the rectangular shape shown in FIG. Moreover, the opening area of the inlet 23h and the outlet 23i is set according to the required cooling capacity and the like.

  The battery module having the above configuration is assembled as follows.

  First, spacer portions 25a are attached to the bipolar terminals 104 and 105 of the eight thin batteries 10 and accommodated in the lower case 23, and sleeves 25d are inserted into the respective through holes 25a1 of the spacer portions 25a. Next, the cushioning material 25e is placed on the upper and lower surfaces of each spacer portion 25a, and the lower case 23 is covered with the upper case 24. 23 and the upper case 24 are fixed.

  In the thin battery 10 according to this embodiment using a flexible sheet-like member as the exterior members 106 and 107, it is necessary to keep the distance between the electrode plates 101 and 103 uniform in order to maintain the battery performance. On the other hand, in the present embodiment, the uppermost and lowermost thin batteries 10 are brought into close contact with the upper and lower inner wall surfaces of the case 22, and the thin batteries 10 are accommodated in the case 22 in a state of being brought into close contact with each other. It is possible to apply pressure in the stacking direction of the electrode plates 101 and 103.

  In addition, since each thin battery 10 and the upper and lower surfaces of the case 22 are in close contact with each other, it is possible to radiate heat from each thin battery 10 through the upper and lower surfaces of the case 22. Yes.

  As shown in FIGS. 4 and 5, the assembled battery 30 according to the present embodiment is configured using twelve battery modules 20 described above. In each battery module 20, the lead-out direction of the electrode terminals 104 and 105 of the secondary battery 10 is along the direction from the inlet side opening 31 b of the container 31 toward the outlet side opening 31 c, and the introduction is formed in the case 22. The outlets 23h are positioned on the inlet side opening 31b side, and the discharge side openings 23i are positioned on the outlet side opening 31c side, and are arranged in three rows and four rows in the internal space 31a of the container 31.

  Collars (not shown) are interposed between the battery modules 20 stacked in three stages, and the battery modules 20 are stacked with a space therebetween. A partition member 35 is provided between the battery modules 20 adjacent to each other. The output terminals 25f and 25g of each battery module 20 are connected in a desired connection form such as serial connection or parallel connection through a cable or the like. As a result, each battery module 20 is a terminal that is led out from the container 31 to the outside. (Not shown) is electrically connected.

  The partition member 35 is a plate-like elastic body independent of the case 22 of each battery module 20, and the introduction port 23 h and the discharge port formed in the respective long side portions 23 a 1 facing each other between the adjacent battery modules 20. 23i is blocked. In this embodiment, it is possible to adjust the introduction amount of the cooling air by adjusting only the shape of the partition member 35 by configuring the partition member 35 by a member independent of the case 22. The case 22 of the battery module 20 is shared. In the present invention, the function of the partition member 35 may be imparted to the case 22 itself, without being particularly limited thereto.

  Examples of the material constituting the partition member 35 include low-hardness materials such as soft rubber and sponge. By constituting the partition member 35 with these materials, the space between the battery modules 20 can be satisfactorily sealed.

  In the present embodiment, as shown in FIGS. 5 and 6, it is possible to block between the three battery modules 20 by one partition member 35. At this time, a total of six groove portions 35a extending in the longitudinal direction are formed in the partition member 35, and the crimping portion 23c protruding from the side surface portion 23a1 of the case 22 can be allowed. Yes.

  Further, as shown in FIG. 7, the partition member 35 has an inclined portion 35b around the introduction port 23h of the case 22 for directing the refrigerant toward the introduction port 23h. The inclined portion 35b is inclined so as to approach the case 22 from the inlet side opening 31b toward the outlet side opening 31c, and has an inclination of an angle θ with respect to the direction from the inlet side opening 31b toward the introduction side opening 31c. ing. A specific angle θ is about 15 °.

  The partition member 35 in the present embodiment also has an inclined portion around the discharge port 23 i of the case 22. This inclined portion is inclined opposite to the inclined portion 35b on the introduction port 23h side, that is, inclined away from the case 22 from the inlet side opening 31b toward the outlet side opening 31c.

  Next, the operation will be described.

  First, when the fan 34 of the assembled battery 30 is driven to rotate, negative pressure is generated in the inlet side duct 32 and the container 31, and cooling air is taken into the container 31 from the outside of the assembled battery 30 through the inlet side duct 32. .

  The cooling air taken into the internal space 31a from the inlet duct 32 through the inlet opening 31b of the container 31 enters a space formed between the battery modules 20. The case 22 itself of each battery module 20 is cooled by the cooling air passing through this space, and each thin battery 10 accommodated in the case 22 is cooled via the case 22.

  Further, as shown in FIG. 4, a part of the cooling air that has entered the space formed between the battery modules 20 passes through the internal space of the container 31 from the inlet 23 h formed in the case 22 of each battery module 20. Entering 31a, the cooling air comes into contact with the inclined surface portion and the heat-sealed portion of the exterior member 106 of each thin battery 10, and the thin battery 10 is cooled.

  At this time, in the present embodiment, the gap between the introduction port 23h and the discharge port 23i is blocked by the partition member 35 between the battery modules 20, so that the battery module 20 is positively introduced through the introduction port 23h. It is possible to incorporate cooling air.

  Moreover, in this embodiment, since the partition member 35 has the inclined part 35a around the introduction port 23h, it is possible to take cooling air into the battery module 20 more positively.

  The cooling air that has cooled the thin battery 10 in the case 22 is discharged to the outside of the case 22 from the discharge port 23i formed in the case 22, and together with the cooling air that has passed through the space between the battery modules 20, the container 31 to the outlet side opening 31c, and is further discharged to the outside of the assembled battery 30 through the outlet side duct 33 by driving the fan 34. In the present invention, the refrigerant supplied by the refrigerant supply means is not limited to cooling air, and may be gas or liquid.

  As described above, in the present embodiment, the introduction port 23h and the discharge port 23i are provided in the case 22 of the battery module 20, and the partition member 35 is provided between the battery modules 20 so as to block them. Thereby, since the cooling air can be actively taken into the case 22 through the introduction port 23h, the thin battery 10 constituting the battery module 20 can be efficiently cooled.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, in the above-described embodiment, it has been described that the battery module 20 is configured by using the eight thin batteries 10, but the present invention is not particularly limited thereto, and an arbitrary number of thin secondary batteries are used. The battery module can be configured. Further, in the above-described embodiment, the description has been made so that the assembled battery 30 is configured by arranging the twelve battery modules 20 in three stages and four rows. However, the present invention is not particularly limited thereto, and any number of battery modules 20 may be provided. The battery module can be configured by arranging battery modules in an arbitrary arrangement.

FIG. 1 is a plan view showing an entire thin battery according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the secondary battery taken along line II-II in FIG. FIG. 3 is an overall perspective view of the assembled battery according to the embodiment of the present invention. 4 is a cross-sectional view showing an arrangement of battery modules constituting the assembled battery shown in FIG. FIG. 5 is a cross-sectional view taken along line VV in FIG. FIG. 6 is an enlarged cross-sectional view of a VI part in FIG. FIG. 7 is an enlarged cross-sectional view of a portion VII in FIG. FIG. 8 is a perspective view showing the battery module in the embodiment of the present invention. 9 is an exploded perspective view showing the assembled battery shown in FIG. 8 upside down and further disassembled.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Thin battery 101 ... Positive electrode plate 101a ... Positive electrode side collector 101b, 101c ... Positive electrode layer 102 ... Separator 103 ... Negative electrode plate 103a ... Negative electrode side collector 103b, 103c ... Negative electrode layer 104 ... Positive electrode terminal 105 ... Negative electrode terminal 106 ... Upper exterior member 107 ... Lower exterior member 108 ... Power generation element 20 ... Battery assembly 21 ... Battery stack 22 ... Case 22a ... Caulking part 23 ... Lower case 23a ... Side face part 23a1 ... Long side face part 23b ... Edge part 23d- 23f ... 1st to 3rd notch 23g ... Through-hole 23h ... Inlet 23i ... Outlet 24 ... Upper case 24a ... Edge 24b ... Through-hole 25a ... Spacer 25a1 ... Through-hole 25b ... Insulation cover 25c ... Female connector 25d ... Sleeve 25e ... Buffer material 25f ... Positive electrode output terminal 25g ... Negative electrode output terminal 30 ... Battery pack 31 ... Container 31a ... Inner space 31b ... Inlet side opening 31c ... Outlet side opening 32 ... Inlet side duct 33 ... Outlet side duct 34 ... Fan 35 ... Partition member 35a ... Groove part 35b ... Inclined part θ ... Angle of inclining part

Claims (4)

The electrode plates laminated via the separator are accommodated in the exterior member and sealed, and a plurality of secondary batteries in which the electrode terminals connected to the electrode plates are led out from the outer peripheral edge of the exterior member are laminated, A plurality of battery modules housing the body in a case;
Refrigerant supply means for supplying a refrigerant for cooling the secondary battery,
The plurality of battery modules are arranged side by side and stacked,
An inlet for introducing the refrigerant supplied from the refrigerant supply means into the case on at least one surface of the case, and an outlet for discharging the refrigerant introduced into the case through the inlet And are provided,
An assembled battery further comprising partition means for blocking between the introduction port and the discharge port formed on at least one surface of the case between the battery modules.   The assembled battery according to claim 1, wherein the partitioning means is formed of a member independent of the case.   The assembled battery according to claim 1 or 2, wherein the partitioning means is made of an elastic body. The assembled battery according to any one of claims 1 to 3, wherein the partitioning unit has an inclined portion for directing the refrigerant supplied from the refrigerant supply unit toward the introduction port around the introduction port of the case.

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