JP4887944B2 - Storage device manufacturing apparatus and storage module manufacturing method - Google Patents

Description

  The present invention relates to a power storage module manufacturing apparatus and a power storage module manufacturing method.

  Some battery packs include a battery module including a single battery cell and a battery module in which a plurality of battery cells are integrally fixed. In the battery pack, the battery module is housed in a battery case. Since the battery module includes a plurality of battery cells, it is possible to extract a large current or a large voltage.

  In recent years, an electric vehicle using an electric motor as a drive source and a so-called hybrid electric vehicle combining an electric motor and another drive source have been put into practical use. A battery pack provided with a battery module is mounted on such an automobile, for example. As the battery cell, for example, a secondary battery represented by a nickel-cadmium battery, a nickel-hydrogen battery, a lithium ion battery, or the like that can be repeatedly charged and discharged is used.

  Japanese Patent Application Laid-Open No. 2005-339929 discloses a method of manufacturing a battery module in which a flat secondary battery is sandwiched between end plates, in which the secondary battery and the end plate are stacked, and the thickness of the stacked body is increased. A method for manufacturing a battery module is disclosed in which a load is repeatedly applied in the vertical direction and the stack is then restrained. In this manufacturing method, during repeated loading, the load on the laminate is changed between a smaller load and a larger load at the time of restraint. This battery module manufacturing method discloses that a battery module having stable performance over a long period of time can be manufactured by preventing load loss due to passage of time or use.

  In Japanese Patent Application Laid-Open No. 6-251808, a separator plate and an intermediate electrode, which are component parts of a battery body, are laminated, and a bolt is minimum tightened by a test piece using the same components as the separator plate and the intermediate electrode in advance. The final tightening force is calculated by adding to this minimum tightening force factors such as the creep amount of the component material caused by ambient thermal changes and the surface pressure necessary to saturate the creep in a short time. There is disclosed a method for manufacturing a zinc-bromine battery that is determined by calculation and in which a plurality of bolts are equally tightened diagonally. In this method of manufacturing a zinc-bromine battery, it is disclosed that in the method of obtaining a battery body integrally laminated and fixed, the best manufacturing process and conditions can be determined and a clear index can be provided at the time of assembly. Has been.

In Japanese Patent Laid-Open No. 2001-236937, an assembled battery in which square battery cells constituting a flat plate are stacked in the thickness direction is accommodated horizontally in an assembled battery case, and the assembled battery is provided at both ends in the stacking direction. A pair of constraining plates that are respectively abutted against the respective rectangular battery cells are provided, and the pair of constraining plates are formed by the connecting lot so that all the square battery cells between them are pressed. An interconnected battery pack is disclosed. According to this battery pack, it is disclosed that the expansion of each square battery cell constituting the assembled battery can be reliably prevented.
JP 2005-339929 A JP-A-6-251808 JP 2001-236937 A

  In the battery module, a plurality of battery cells and a frame member are stacked to form a stacked body, and end plates are arranged on both sides of the stacked body. The end plates on both sides are integrated by being fixed with, for example, a round bar as a restraining member.

  The battery cells included in the stacked body and the frame members arranged between the battery cells cause a manufacturing error in size in each manufacturing. For example, in a battery cell, there are variations in the plate thickness between the electrode body and the battery case (accommodating case), and manufacturing errors occur in the stacking direction. The frame member formed of resin causes a variation in molding at the time of resin molding, and a manufacturing error occurs in the stacking direction. Since the laminated body is configured by laminating battery cells and frame members in which errors have occurred in each of the laminated bodies, variations in dimensions also occur in the overall length of the laminated body.

  When the laminated body is sandwiched between end plates and the end plates are fixed with a restraining member, a load is applied in a direction in which the end plates approach each other. When fixing with a restraining member, it is possible to fix the length of the laminated body in the laminating direction, for example. However, in this method, there is a problem that the variation in the restraint load applied to the laminate increases.

  For example, a battery such as a lithium ion battery has a binding load range in which excellent performance can be exhibited. When the load range that guarantees the performance is exceeded and the restraint member is strongly restrained, the output of the battery cell may be reduced. Alternatively, if the load is below the load range that guarantees the performance and is weakly restrained by the restraining member, gas may be generated inside the battery cell if the use is continued, resulting in a problem that the life of the battery cell is shortened.

  In addition, if the battery cell and the frame member are restrained without applying an appropriate load and the use of the battery module is continued, the creep amount of the frame member formed of resin increases and is applied to the battery cell. There exists a problem that there exists a possibility that a load may deviate from the load range which guarantees performance.

  Alternatively, when the end plates are fixed with a restraining member, it may be possible to press the end plates with a constant load. In this case, however, there is a problem that variation in the total length of the battery modules in the stacking direction becomes large. .

  An object of the present invention is to provide a power storage module manufacturing apparatus and a power storage module manufacturing method capable of manufacturing a power storage module capable of stable driving over a long period of time in a short time.

  A power storage module manufacturing apparatus according to the present invention is a power storage module manufacturing apparatus including a stacked body in which power storage cells and a frame member formed of a resin are stacked, and applies a load in the stacking direction of the stacked body. A load application unit is provided. A heating unit for heating the frame member is provided. The heating unit is formed to heat the frame member when a load is applied to the laminate. The load application section is formed so as to apply a load so that the length of the laminate in the stacking direction is within a specified range.

  A method for manufacturing a power storage module according to the present invention is a method for manufacturing a power storage module including a stacked body in which power storage cells and a frame member formed of a resin are stacked, and applies a load in the stacking direction of the stacked body. A load applying step; and a fixing step of restraining the laminated body with a restraining member in the laminating direction after the load applying step. The load applying step includes a step performed while heating the frame member. The load applying step includes a step of applying a load so that a length of the stacked body in the stacking direction is within a specified range.

  In the above invention, preferably, a lithium ion battery is used as the electricity storage cell.

  According to the present invention, it is possible to provide a power storage module manufacturing apparatus and a power storage module manufacturing method capable of manufacturing a power storage module capable of stable driving over a long period of time.

  With reference to FIGS. 1 to 5, a power storage module manufacturing apparatus and a power storage module manufacturing method according to an embodiment of the present invention will be described. The power storage pack includes a power storage module and a case, and the power storage module is accommodated in the case.

  FIG. 1 is a schematic perspective view of a battery module as a power storage module in the present embodiment. Battery module 10 in the present embodiment is mounted on an automobile. The battery module 10 is mounted on a hybrid vehicle that uses an internal combustion engine such as a gasoline engine or a diesel engine and a rechargeable secondary battery as power sources.

  The battery module 10 includes a battery cell 33 as a storage cell. The battery module 10 includes a stacked body in which a plurality of battery cells 33 are stacked. The plurality of battery cells 33 are stacked in the thickness direction of the battery cell 33. An arrow 89 indicates the stacking direction of the battery cells 33. In battery module 10 in the present embodiment, battery cells 33 are stacked in two rows.

  The battery cell 33 in the present embodiment is formed in a flat plate shape. The battery cell 33 is a square battery cell. Battery cell 33 in the present embodiment includes a lithium ion battery. The plurality of battery cells 33 are electrically connected to each other by a bus bar (not shown).

  The laminated body in the present embodiment includes a battery holder 15 as a frame member arranged so as to sandwich each battery cell 33. A battery holder 15 is disposed between adjacent battery cells 33 in the stacking direction of the battery cells 33. The battery holder 15 sandwiches the battery cell 33. One battery cell 33 is sandwiched in the stacking direction by two battery holders 15 arranged on both sides of the one battery cell 33.

  The battery holders 15 are arranged in the stacking direction of the battery cells 33. In the present embodiment, the battery cells 33 and the battery holders 15 are alternately arranged in the stacking direction of the battery cells 33.

  The battery holder 15 is made of an electrically insulating material. Battery holder 15 in the present embodiment is made of resin. The battery holder 15 is made of, for example, a resin material such as polypropylene or a polymer of polypropylene. The battery holder 15 electrically insulates the battery cells 33 adjacent in the stacking direction.

  The battery module 10 includes end plates 40 disposed on both sides in the stacking direction of the stacked body. The end plate 40 in the present embodiment is formed in a plate shape. End plate 40 in the present embodiment is formed of resin. The end plate 40 is disposed so as to sandwich the battery cell 33 and the battery holder 15 from both sides in the stacking direction.

  The battery module 10 includes a restraining band 42 as a restraining member. The restraining band 42 in the present embodiment is formed in a plate shape. The restraining band 42 is formed to have a longitudinal direction. The restraint band 42 is arranged so that the longitudinal direction extends in the stacking direction of the battery cells 33. The restraint band 42 in the present embodiment is adjusted in thickness and width so that sufficient strength can be secured.

  The restraint band 42 is disposed so as to fasten the end plates 40 to each other. The restraint band 42 is fixed to the end plate 40 by a bolt 50 as a fastening member. The restraining band 42 is disposed so as to restrain the battery cell 33 in the stacking direction. The plurality of battery holders 15 and the battery cells 33 are integrally held by a restraining band 42.

  The battery holder 15 has an exhaust gas flow path portion 30. The exhaust gas flow path section 30 constitutes an exhaust gas flow path for circulating the gas discharged from the battery cell 33. The exhaust gas flow path part 30 is formed in a convex shape. The exhaust gas flow path part 30 is formed so as to protrude from the surface of the battery holder 15. The exhaust gas flow path part 30 is formed so that the inside becomes a cavity. The exhaust gas flow path section 30 in the present embodiment is formed so that the cross-sectional shape is a U-shape.

  The exhaust gas flow path portions 30 of the respective battery holders 15 are arranged so as to communicate with each other. The exhaust gas flow path part 30 extends along the stacking direction of the battery cells 33. An exhaust pipe 31 is connected to the end of the exhaust gas flow path section 30.

  The battery pack in the present embodiment includes a safety valve (not shown) in the main body. This safety valve is formed to open when the air pressure inside the battery holder 15 exceeds a set value. When the safety valve is opened, the air inside the battery holder 15 can be released to the outside through the exhaust gas flow passage portion 30 and the exhaust pipe 31.

  FIG. 2 is an exploded perspective view of the end portion of the battery module in the present embodiment. FIG. 3 shows a schematic cross-sectional view of the battery pack in the present embodiment. FIG. 3 is a cross-sectional view taken along the line III-III in FIG.

  With reference to FIGS. 1 to 3, battery cell 33 in the present embodiment has electrode 33 a. The electrode 33a is formed in a plate shape. The electrode 33 a is formed so as to protrude from the end face of the battery cell 33. The electrode 33a is formed to face the outside of the battery holder 15. The electrode 33 a is formed so as to jump out from the surface 22 of the battery holder 15. The battery holder 15 is formed such that the electrodes 33a are exposed from between the adjacent battery holders 15.

  The battery cell 33 has a pair of surfaces 33b facing each other. The surface 33 b is an area maximum surface having the largest area among the plurality of surfaces of the battery cell 33. The plurality of battery cells 33 are arranged such that the surfaces 33b are substantially parallel to each other.

  Battery holder 15 includes a base portion 21. The base part 21 has a rib 21a. The rib 21a is formed in a linear shape. The ribs 21 a are formed so as to protrude from the surface of the base portion 21. A plurality of ribs 21a are formed at intervals from each other. In addition, it may replace with the rib 21a and may provide the boss | hub arrange | positioned at dot shape, and may provide it combining a rib and a boss | hub.

  The rib 21 a is in contact with the surface 33 b of the battery cell 33. The battery cell 33 is sandwiched in the stacking direction of the battery cells 33 by being pressed by the rib 21a of the one battery holder 15 and the back surface of the battery holder 15 facing the battery cell 33.

  The battery holder 15 has openings 16 and 17. The openings 16 and 17 in the present embodiment are formed by cutting out the side surface of the battery holder 15. Between the ribs 21a, there is formed a cooling air flow path 100 for circulating the cooling air.

  In the battery module 10, as indicated by an arrow 90, cooling air is taken in from the opening 16 and is discharged from the opening 17 through the cooling air flow path 100. The battery cell 33 is cooled by air flowing along the surface 33 b of the battery cell 33. The battery cell 33 is cooled by the air passing through the flow path 100.

  The restraining band 42 in the present embodiment has a bent portion 42a formed at the end so as to be bent in the cross-sectional shape. The bent portion 42 a is formed so as to be bent along the shape of the edge of the end plate 40. The constraining band 42 has a portion where the surface is substantially perpendicular to the stacking direction by forming bent portions 42a at both ends in the longitudinal direction. This portion is fixed to the end plate 40. The end plate 40 is fixed so as to be sandwiched between the end portions of the restraining band 42.

  The restraining band 42 in the present embodiment is fixed to the end plate 40 by bolts 50. The bolt 50 is arranged so as to extend in the stacking direction of the stacked body indicated by the arrow 89. The bolt 50 is inserted in the stacking direction of the stacked body.

  The storage module manufacturing apparatus in the present embodiment is a battery module manufacturing apparatus. The apparatus for manufacturing a power storage module is not limited to a battery module manufacturing apparatus, and the present invention can be applied to a power storage module manufacturing apparatus including an arbitrary power storage cell.

  The battery module manufacturing apparatus includes a load application unit that applies a load in the stacking direction of the stacked body. The load application part in this Embodiment contains the load application member arrange | positioned at the both sides of the lamination direction of a laminated body. The load applying members are arranged so as to face each other. The load application member is formed so as to sandwich the laminate. The load application portion is formed so that a pressing force can be applied to the laminate by moving the load application members in a direction approaching each other. The load application unit in the present embodiment is formed so as to apply a load so that the length of the stacked body in the stacking direction is within a specified range.

  The battery module manufacturing apparatus according to the present embodiment includes a heating unit for heating the frame member. The heating unit is formed to increase the temperature of the frame member. The heating unit is formed to heat the frame member when a load is applied to the laminate. The heating unit in the present embodiment is formed so that a laminated body can be disposed therein. The heating unit is formed so that the temperature around the entire laminate can be raised.

  FIG. 4 shows a graph for explaining the relationship between the load applied to a member formed of resin and the amount of creep at that time. The horizontal axis represents the load applied to the resin member, and the vertical axis represents the creep amount of the resin member. The creep amount tends to increase as the load applied to the resin member increases.

  Referring to FIGS. 1 and 2, in the method for manufacturing the power storage module according to the present embodiment, a load applying step of applying a load to the stacked body is performed along the stacking direction indicated by arrow 89. After the battery cell 33, the battery holder 15 and the end plate 40 are arranged in the stacking direction, a load is applied in the stacking direction. The direction in which the load is applied is a direction in which the end plates 40 approach each other as indicated by an arrow 91. That is, a load that compresses in the stacking direction is applied to the stacked body of the battery cells 33 and the battery holder 15.

  The load application step in the present embodiment is performed while heating the frame member. In the present embodiment, the entire laminate is heated. In the present embodiment, an atmosphere of about 40 ° C. or more and about 60 ° C. or less is formed in the heating unit, and the load application step is performed in this atmosphere. In the load application step, the load is applied by sandwiching the laminate with the load application member of the battery module manufacturing apparatus.

  Creeping can be promoted by increasing the temperature of the battery holder and end plate made of resin and applying a load. As a result, a necessary amount of creep can be promoted in a short time. That is, the load application process can be completed in a short time.

  Referring to FIG. 3, in the load application step in the present embodiment, a load is applied so that the length in the stacking direction is within a predetermined range. In the present embodiment, the progress of creep is determined by measuring the distance L between the outer end faces of the end plate 40. When the distance L is within the specified range, the application of the load is stopped. For example, the maximum length and the minimum length of the laminate to be finished with the load application are determined, and the load application is finished when the load is within this range.

  Thus, in the present embodiment, the load is applied so that the variation in the dimension in the stacking direction is within the specified value. Alternatively, a load is applied so as to reduce the dimensional variation.

  In the present embodiment, the end plate 40 is made of resin. For this reason, the creep phenomenon of the resin parts appears in the end plate 40 in addition to the battery holder 15. In the present embodiment, the end plate creep can be simultaneously promoted by pressing the end surfaces of the end plates and measuring the distance L between the end surfaces of the end plates.

  In the load application step, in addition to a method of applying a constant load, a method of applying an arbitrary load such as a method of gradually increasing the load, a method of repeatedly applying a large load and a small load can be adopted. .

  FIG. 5 shows a graph for explaining the change over time of the restraining load of the stack of power storage modules. The horizontal axis is time, and the vertical axis is restraint load. The graph shown in FIG. 5 shows a case where the initial restraining load is maximized and a case where the initial restraining load is minimized due to the manufacturing error of each laminate.

  The case where the initial restraining load is maximum is, for example, when the length of the storage module in the stacking direction is the longest. When the initial restraining load is minimum, for example, the length of the storage module in the stacking direction is Is the shortest.

  The period from time 0 to time t1 is a period immediately after the load is applied, and is a range in which the restraint load is rapidly reduced as time elapses due to the promotion of creep. After time t1, the restraint load changes gently.

  If the use of the power storage module is continued after time t1, a phenomenon that the battery cell swells may occur. On the other hand, the creep of a resin part such as a battery holder made of resin proceeds slowly. In the case where the initial restraint load is maximum, the phenomenon in which creep progresses prevails over the phenomenon in which the battery cell swells, and the restraint load gradually decreases. On the other hand, in the case where the initial restraint load is minimum, the phenomenon in which the battery swells over the phenomenon in which creep progresses, and the restraint load gradually increases. However, as shown in FIG. 5, the change in the restraint load after time t1 is gradual, and any power storage module can be kept within the load range that guarantees the performance.

  Referring to FIG. 5, in the present embodiment, a load is applied in a load application process during manufacturing until a creep amount corresponding to time t1 is obtained. In the present embodiment, the length in the stacking direction of the stacked body is measured as described above as a method for determining whether or not the creep amount corresponding to time t1 has been obtained. That is, the load application process is continued until the length of the laminated body falls within a specified range.

  Moreover, in the load application process in this Embodiment, it is performed, monitoring a load amount with the load cell as a load monitoring part arrange | positioned at the load application part. The applied load is equal to the reaction force of the stack of power storage modules. The reaction force of the laminated body is determined by (compressed length in the lamination direction of the laminated body) × (spring constant of the laminated body). The prescribed range for terminating the application of the load is determined by the spring constant of these entire laminates and the load range that guarantees the performance of the storage cell.

  By performing the load application process until the period immediately after the load application up to time t1 has elapsed, the subsequent change in the restraint load can be moderated, and the stable storage cell can be restrained. Therefore, it is possible to provide a power storage module that can be driven stably over a long period of time.

  After the load application step, the laminate is restrained by a restraining band. The restraining member is not limited to the restraining band, and any member that restrains the laminate can be used.

  As in this embodiment, a large restraint load applied to the power storage module can be avoided by applying a load in advance and advancing the creep phenomenon immediately after the load is applied. For example, in FIG. 5, a large restraint load at time 0 can be avoided. As a result, for example, the strength of a member for performing restraint such as a restraint band or an end plate can be reduced, and the power storage module can be reduced in weight and size.

  In the present embodiment, the load is applied so that the creep proceeds until the period immediately after the load is applied. However, the present invention is not limited to this mode, and it is determined in advance even if the creep is not completely advanced. The load may be continued until it falls within the predetermined range.

  In this embodiment, a lithium ion battery is used as the storage cell. When using a lithium ion battery, the load range which guarantees the performance peculiar to a lithium ion battery is set. If the load range that guarantees the performance is deviated, for example, the battery life may be shortened or the battery performance may not be fully exhibited. For this reason, in a load application process, the magnitude | size of the load to apply and the predetermined value of the length of the lamination direction which should stop a load application are set according to the kind of electrical storage cell to be used, respectively.

  In the present embodiment, the length of the end faces of the end plates is measured as a parameter to be monitored in the load application step, but the length is not limited to this form. For example, the end face of the stack of battery holders and battery cells You may measure the distance between each other.

  In the present embodiment, the end plates disposed on both sides of the stacked body of storage cells are both formed of resin. However, the present invention is not limited to this mode. For example, the end plates may be formed of metal. . Moreover, although the end plate in this Embodiment is formed in flat form, it is not restricted to this form, Arbitrary shapes can be employ | adopted.

  Although the battery cell in this Embodiment is a lithium ion battery, it is not restricted to this form, This invention is applicable to a battery module provided with arbitrary battery cells. For example, the battery cell may include a nickel metal hydride battery. Moreover, as an electrical storage cell, it is not restricted to this form, What is necessary is just to have the function to store electricity. For example, the electricity storage cell may include a capacitor.

  Moreover, although the electrical storage cell in this Embodiment is formed in flat form, it is not restricted to this form, This invention is applicable to the electrical storage module containing the electrical storage cell of arbitrary shapes.

  In the present embodiment, the hybrid vehicle that drives the internal combustion engine at the fuel efficiency optimum operating point is described as an example among the hybrid vehicles. However, the present invention is not limited to this embodiment, and a fuel cell and a secondary battery are used as drive sources. The present invention can also be applied to a fuel cell hybrid vehicle (FCHV) or an electric vehicle (EV). Furthermore, the present invention is not limited to a power storage module disposed in an automobile, but can be applied to a power storage module in which arbitrary power storage cells are stacked.

  In the respective drawings described above, the same or corresponding parts are denoted by the same reference numerals.

  In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It is not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic perspective view of the battery module in the embodiment. It is an expansion disassembled perspective view of the edge part of the battery module in embodiment. It is a schematic sectional drawing of the battery module in embodiment. It is a graph explaining the load and creep amount which are applied to the member formed with resin. It is a graph explaining the time change of the restraint load when a load is applied to a battery module.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Battery module, 15 Battery holder, 16, 17 Opening part, 21 Base part, 21a Rib, 22 Surface, 30 Exhaust gas flow path part, 31 Exhaust pipe, 33 Battery cell, 33a Electrode, 33b Surface, 40 End plate, 42 Restraint Band, 42a Bent part, 50 volts, 89-91 arrow, 100 flow path.

Claims (3)

An electrical storage module manufacturing apparatus comprising a laminate in which an electrical storage cell and a frame member formed of resin are laminated,
A load application unit for applying a load in the stacking direction of the laminate,
A heating unit for heating the frame member,
The heating unit is formed to heat the frame member when a load is applied to the laminate.
The said load application part is a manufacturing apparatus of the electrical storage module formed so that a load may be applied so that the length of the said lamination direction of the said laminated body may become in a regulation range. A method for manufacturing an electricity storage module comprising a laminate in which an electricity storage cell and a frame member formed of a resin are laminated,
A load application step of applying a load in the stacking direction of the laminate,
After the load application step, including a fixing step of restraining the laminated body with a restraining member in the laminating direction,
The load applying step includes a step performed while heating the frame member,
The load applying step includes a step of applying a load so that a length of the stacked body in the stacking direction is within a specified range.   The manufacturing method of the electrical storage module of Claim 2 using a lithium ion battery as the said electrical storage cell.

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