JP2009048964A - Method of manufacturing secondary battery, and electrolytic solution infiltration state determining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of easily and accurately determining an infiltration state of an electrolytic solution into an electrode body, to provide a device therefor, and to provide a method of manufacturing a secondary battery using the determining method. <P>SOLUTION: The method of manufacturing the secondary battery includes a process of housing an electrode body 30 and an electrolytic solution E in a container 12 to construct a battery assembly 20, a process of immersing the electrode body 30 into the electrolytic solution E and infiltrating the electrolytic solution into the electrode body 30, a process of comprehending an extent of downward bias of weight balance of the assembly 20, and a process of comparing the extent of its bias with a set target value in advance. The extent of the bias can be comprehended, for example, by the measurement with a load cell 68 of a force with which the assembly 20 is going to be rotated following the gravity which is kept inclined against the gravity. If the extent of the bias is the same as the target value or less, infiltration is determined sufficient and transfer to the following process is conducted, but if the extent of the bias is larger than the target value, the infiltration is determined insufficient, and the transfer to the following process is temporarily suspended. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a secondary battery having a configuration in which an electrolyte solution penetrates into an electrode body and a method of determining an electrolyte solution penetration state into the electrode body. Moreover, this invention relates to the electrolyte solution penetration state determination apparatus suitable for implementation of this method.

  2. Description of the Related Art Secondary batteries (for example, lithium ion batteries) having a configuration in which an electrode body in a form in which sheet-like electrodes are typically stacked via a sheet-like separator are housed together with a liquid electrolyte (electrolytic solution) are known. ing. In one typical method for manufacturing this type of battery, the electrolyte is infiltrated into the electrode body by immersing the electrode body in the electrolyte in the container. If the battery is charged / discharged with insufficient penetration of the electrolyte into the electrode body, the original battery performance may not be exhibited, or the battery may be deteriorated. For this reason, it is preferable that the state in which the electrolyte solution is sufficiently permeated is realized at the latest before shipment of the battery product. In a secondary battery that is commercialized through a so-called conditioning process in which initial charge / discharge is performed after the battery components are assembled, it is preferable that the electrolyte solution is sufficiently infiltrated before the conditioning process.

  Patent Document 1 describes that the state of impregnation of the electrolyte into the electrode body is determined by measuring the capacitance and / or impedance between the positive and negative electrodes. Patent Document 2 relates to a technique for accurately injecting a predetermined amount of electrolyte into a battery container.

JP 2002-110252 A JP-A-11-185895

  However, the capacitance and impedance between the positive and negative electrodes can vary greatly depending on various factors other than the state of penetration of the electrolyte (for example, variations in electrode manufacturing, the wound state of the electrode body, etc.). It would be beneficial if the permeation state of the electrolyte could be grasped more accurately and easily.

  Therefore, an object of the present invention is to provide a method for easily and accurately determining the state of penetration of an electrolytic solution into an electrode body and a determination device suitable for carrying out the method. Another object of the present invention is to provide a method of manufacturing a secondary battery by applying the determination method.

  In the battery assembly having a configuration in which the electrode body and the electrolyte solution are accommodated in the container, the inventor determines the arrangement (weight distribution) of the electrolyte solution in the container depending on the degree of penetration of the electrolyte solution into the electrode body. Therefore, attention was paid to the fact that the weight balance in the vertical direction (vertical direction) of the assembly is different. And it discovered that the said subject could be solved by using the deviation of this weight balance for a parameter | index, and completed this invention.

  The secondary battery manufacturing method provided by the present invention includes a step of constructing a battery assembly by housing an electrode body and an electrolytic solution in a form in which sheet-like electrodes are overlaid in a container. The manufacturing method also includes a step of immersing the electrode body in the electrolytic solution and allowing the electrolytic solution to permeate the electrode body. A step of grasping a degree of deviation of the weight balance of the assembly in the vertical direction; Further, the method includes a step of comparing the degree of the deviation with a preset target value. Here, when the degree of the deviation is equal to or less than the target value, it is determined that the electrolyte has sufficiently penetrated, and the process proceeds to a downstream process (for example, a conditioning process). On the other hand, when the degree of the deviation is larger than the target value, it is determined that the electrolyte solution has not sufficiently penetrated, and the shift to the downstream process is suspended.

Since the electrolyte solution that has not penetrated into the electrode body (hereinafter also referred to as “residual electrolyte solution”) can easily move (flow) according to the gravity, the electrolyte in the container in the posture is in accordance with the posture of the battery assembly. It accumulates on the lower side in the vertical direction (hereinafter sometimes simply referred to as “lower”). On the other hand, the electrolytic solution that has permeated (permeated) the electrode body is held at the permeated position regardless of the posture of the container. For this reason, the greater the amount (weight) of the residual electrolyte solution, the greater the degree of bias toward the lower side of the weight balance when the assembly is in a predetermined posture. The amount of the residual electrolyte corresponds to the remaining amount obtained by subtracting the amount of the electrolyte that has permeated the electrode body from the amount of the electrolyte supplied in the container. Therefore, when the amount of the residual electrolyte is larger than a preset target value (typically set based on the amount of the residual electrolyte when the electrolyte sufficiently penetrates the electrode body). It can be said that the penetration of the electrolytic solution into the electrode body is insufficient.
According to the method disclosed herein, by grasping the amount of the residual electrolyte as the degree of the bias to the lower side of the weight balance of the battery assembly, the state of penetration of the electrolyte into the electrode body (the electrode body penetrated) The amount of the electrolytic solution) can be accurately grasped. Therefore, the assembly that has been determined to have sufficient penetration of the electrolyte moves to the downstream process (closer to the completion of the product), and the assembly that has been determined to have sufficient penetration of the electrolyte has sufficient electrolyte. By taking measures to improve the permeation state such as extending the permeation process until permeation, or removing it from the production line, a secondary battery with stable quality (battery performance) can be stably produced.

  In the present specification, the “battery” is a term indicating a general power storage device that can extract electric energy, and includes a primary battery and a secondary battery. Further, in the present specification, the “secondary battery” is a concept including so-called storage batteries such as lithium ion batteries, metal lithium secondary batteries, nickel metal hydride batteries, nickel cadmium batteries, and power storage elements such as electric double layer capacitors. .

According to the present invention, for a battery assembly having a configuration in which an electrode body in a form in which sheet-like electrodes are overlapped and an electrolytic solution are housed in a container, a method for determining a permeation state of the electrolytic solution into the electrode body Is provided. The method includes the step of grasping the degree of deviation of the weight balance of the assembly in the vertically downward direction. Further, the method includes a step of comparing the degree of the deviation with a preset target value. Further, when the degree of bias is less than or equal to the target value, it is determined that the electrolyte solution has sufficiently penetrated, and when the degree of bias is greater than the target value, the electrolyte solution has penetrated. Including a step of determining that it is insufficient. According to such a method, as in the secondary battery manufacturing method described above, the state of penetration of the electrolytic solution into the electrode body is obtained by grasping the amount of the residual electrolytic solution as the degree of the bias toward the lower side of the weight balance of the battery assembly. Can be accurately grasped.
Note that any one of the electrolyte solution penetration state determination methods disclosed herein is preferably used in the manufacturing process of a battery (typically a secondary battery), and the electrolyte solution penetration state of a completed battery is determined. Can also be preferably used. Therefore, the “battery assembly” in the determination method disclosed herein can be a completed battery (battery product).

The degree of unevenness of the weight balance can be suitably grasped as follows, for example. That is, the assembly is supported so that the lower part of the assembly can rotate with respect to the upper part, and the assembly is tilted against gravity (for example, approximately 30 to the posture according to the gravity). (An attitude inclined by about 45 ° to 45 ° is preferable.). Then, the degree of the weight balance deviation is grasped by measuring the moment force generated when the assembly tries to rotate to take a posture according to gravity. According to such a method, it is possible to easily and accurately grasp the deviation of the weight balance and accurately determine the state of penetration of the electrolytic solution into the electrode body.
The moment force is measured, for example, by placing a measuring device (measuring unit) such as a load meter or its measuring terminal at a position that prevents the assembly from rotating from an inclined posture against gravity to a posture according to gravity. It can implement preferably by arrange | positioning. By comparing the measured value by the measuring instrument (corresponding to the moment force) with a preset target value, when the measured value is equal to or less than the target value, the penetration of the electrolyte solution has sufficiently progressed If the measured value is larger than the target value, it can be determined that the penetration of the electrolytic solution is insufficient.

  As an aspect for supporting the assembly, an aspect in which the assembly is supported by using two opposing portions of the assembly as fulcrums can be preferably employed. For example, when the said container is a rectangular parallelepiped shape, it is preferable to use the location where the two parallel surfaces of this rectangular parallelepiped oppose each other as a fulcrum. According to this aspect, the assembly can be appropriately supported (for example, suspended) by a simple mechanism.

  One of the secondary battery manufacturing methods and the electrolyte solution permeation state determination methods disclosed herein includes a battery (typically two batteries) including a wound electrode body in which stacked sheet-like electrodes are wound in a longitudinal direction. The secondary battery can be applied particularly preferably. In such a wound electrode body, the path through which the electrolyte solution permeates is mainly limited to the end face in the axial direction of the wound electrode body, and therefore it is difficult to estimate the time required until a sufficient permeation state is realized. Therefore, the effect by applying the method of the present invention can be exhibited particularly well. In addition, since the electrolytic solution that has once permeated the wound electrode body is reliably maintained inside the electrode body (permeation position), the electrolytic solution that has permeated the electrode body and the electrolytic solution that has not permeated the electrode body (residual) (Electrolyte) is clearly distinguished. This is convenient for applying the present invention to determine the electrolyte penetration state.

According to the present invention, there is also provided an apparatus for determining a permeation state of the electrolytic solution into the electrode body with respect to a battery assembly having a configuration in which the electrode body and the electrolytic solution are housed in a container. The apparatus includes a support that supports the assembly so that the lower portion of the assembly can rotate relative to the upper portion. For example, a support portion configured to be able to support the assembly with two opposing points of the assembly as fulcrums is preferable. Further, the supported assembly takes a posture according to gravity from a posture inclined against the gravity (for example, a posture inclined approximately 30 ° to 45 ° from the posture according to the gravity is preferable). Therefore, a measuring unit for measuring moment force generated by trying to rotate is provided. Preferably, the measurement unit is disposed at a position that prevents the assembly from rotating from a posture inclined against gravity to a posture according to gravity.
According to the electrolyte solution permeation state determination apparatus having such a configuration, the residual electrolyte amount is set as the degree of bias toward the lower side of the weight balance of the assembly, similarly to the above-described secondary battery manufacturing method and electrolyte solution infiltration state determination method. By grasping | ascertaining, the osmosis | permeation state of the electrolyte solution to an electrode body can be grasped | ascertained correctly. Therefore, the determination apparatus is suitable as an apparatus used in any of the secondary battery manufacturing methods and the electrolyte solution permeation state determination methods disclosed herein.

  A secondary battery (for example, a lithium ion battery) manufactured by any of the methods disclosed herein can be suitably used as a battery mounted on a vehicle. Therefore, according to the present invention, a vehicle (for example, an automobile) provided with a secondary battery manufactured by any of the methods disclosed herein is provided.

Hereinafter, preferred embodiments of the present invention will be described. Note that matters other than matters specifically mentioned in the present specification and necessary for the implementation of the present invention can be grasped as design matters of those skilled in the art based on the prior art in this field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.
The secondary battery manufactured by applying the method according to the present invention can be suitably used as a power source for a motor (electric motor) mounted on a vehicle such as an automobile. Therefore, as schematically shown in FIG. 10, the present invention is a vehicle including such a secondary battery 10 (which may be in the form of an assembled battery formed by connecting a plurality of such batteries 10 in series) as a power source ( An automobile, in particular an automobile equipped with an electric motor such as a hybrid vehicle, an electric vehicle, and a fuel cell vehicle) 1 is provided.

  Although not intended to be particularly limited, in the following, the manufacture of a lithium ion battery in a form in which a wound electrode body (wound electrode body) and a non-aqueous electrolyte are contained in a rectangular (box-shaped) container and The present invention will be described in detail by taking as an example the case where the present invention is applied to the determination of the electrolyte solution permeation state into the wound electrode body. Moreover, in the following drawings, the same code | symbol is attached | subjected to the member and site | part which show | plays the same effect | action, and the overlapping description may be abbreviate | omitted or simplified.

As shown in FIG. 2, for example, the lithium ion battery manufactured according to this embodiment includes a wound electrode body 30 in a form in which sheet-like electrodes are overlapped and wound flat, and the wound electrode body 30. And a container 12 having a shape (in this embodiment, a flat box shape) capable of containing an appropriate electrolytic solution. The material of the container 12 (here, made of metal such as aluminum) may be the same as that used in the conventional sealed battery, and is not particularly limited.
The container 12 has a box-shaped (that is, a bottomed rectangular tube-shaped) container main body 13 having an opening at one end (corresponding to an upper end in a normal use state of the battery according to the present embodiment), and its And a lid body 14 attached to the opening portion and closing the opening portion. The lid body 14 is provided with a positive electrode terminal 15 and a negative electrode terminal 16 for external connection, and a part of the terminals 15 and 16 protrudes outward from the lid body 14. The positive electrode terminal 15 and the negative electrode terminal 16 are electrically connected to the positive electrode and the negative electrode of the wound electrode body 30 accommodated inside the container 12, respectively. The lid body 14 is further provided with an electrolyte solution inlet 17 used for injecting the electrolyte solution E.

  The wound electrode body 30 accommodated in the container 12 includes a long sheet-like positive electrode (positive electrode sheet) 32 and a long sheet-like negative electrode (negative electrode sheet) 34, similarly to a wound electrode body of a normal lithium ion battery. Are laminated together with a total of two long sheet-like separators (separator sheets) (not shown), wound in the longitudinal direction, and then the obtained wound body is crushed from the side direction and kidnapped. obtain. Here, the positive electrode sheet 32 and the negative electrode sheet 34 are laminated so that the positions thereof are slightly shifted in the width direction, and one end in the width direction of the sheets 32 and 34 protrudes from one end and the other end in the width direction of the separator sheet. It is wound in the state. As a result, as shown in FIG. 2, one end in the width direction of the positive electrode sheet 30 is provided at one end and the other end in the winding axis direction of the wound electrode body 12. A portion 32A protruding outward from a portion where the negative electrode sheet 34 and the separator sheet are wound tightly), and a portion 34A where one end in the width direction of the negative electrode sheet 34 protrudes outward from the wound core portion 31; Are formed respectively.

The material and the member constituting the wound electrode body 30 may be the same as the electrode body provided in the conventional lithium ion battery, and are not particularly limited. For example, the positive electrode sheet 32 may have a configuration in which a positive electrode active material layer is formed on a long positive electrode current collector (for example, an aluminum foil). As the positive electrode active material used for forming this positive electrode active material layer, one or two or more materials conventionally used in lithium ion batteries can be used without particular limitation. Preferable examples include lithium transition metal oxides such as LiMn ₂ O ₄ , LiCoO ₂ , and LiNiO ₂ . For example, an aluminum foil having a length of 2 m to 4 m (for example, 2.7 m), a width of 8 cm to 15 cm (for example, 12 cm), and a thickness of about 5 μm to 20 μm (for example, 15 μm) is used as a positive electrode current collector, and a predetermined region on the surface thereof And forming a positive electrode active material layer mainly composed of lithium nickelate (for example, 88% by mass of lithium nickelate, 10% by mass of acetylene black, 1% by mass of polytetrafluoroethylene, 1% by mass of carboxymethylcellulose). A positive electrode sheet 32 is obtained.

  On the other hand, the negative electrode sheet 34 may have a configuration in which a negative electrode active material layer is formed on a long negative electrode current collector (for example, a copper foil). As the negative electrode active material used for forming this negative electrode active material layer, one or two or more materials conventionally used in lithium ion batteries can be used without particular limitation. Preferable examples include carbon-based materials such as graphite carbon and amorphous carbon, lithium transition metal oxides, lithium transition metal nitrides, and the like. For example, a copper foil having a length of 2 m to 4 m (for example, 2.9 m), a width of 8 cm to 15 cm (for example, 12 cm), and a thickness of about 5 μm to 20 μm (for example, 10 μm) is used as the negative electrode current collector. A suitable negative electrode sheet 34 can be obtained by forming a negative electrode active material layer (for example, 98% by mass of graphite, 1% by mass of styrene butadiene rubber, 1% by mass of carboxymethyl cellulose) by a conventional method.

  Preferable examples of the separator sheet wound together with these electrode sheets 32 and 34 include those made of porous polyolefin resin. For example, a porous separator sheet made of a synthetic resin (for example, made of polyolefin such as polyethylene) having a length of 2 to 4 m (for example, 3.1 m), a width of 8 to 12 cm (for example, 10 cm), and a thickness of about 5 to 30 μm (for example, 25 μm) Can be preferably used.

  The main part of the method of manufacturing the lithium ion battery having such a configuration will be described along the flowchart shown in FIG. 1 with reference to the schematic diagrams shown in FIGS. In FIGS. 2 to 4 and FIGS. 5 to 7 to be described later, in order to facilitate understanding of the present invention, a part of the inside of the container 12 is shown through.

  The container 12 and the wound electrode body 30 having the above-described configuration are prepared, and the wound electrode body 30 is accommodated in the container 12 (step S10 shown in FIG. 1). When the electrode body 30 is accommodated in the container 12, for example, first, one end of the positive electrode terminal 15 and the negative electrode terminal 16 (the end extending inside the container 12) provided on the lid body 14 is connected to the positive electrode sheet and the negative electrode. The electrode body 30 and the lid body 14 are coupled by joining (for example, welding) to the protruding portions 32A and 34A of the sheet. Then, the electrode body 30 coupled to the lid body 14 is covered with the lid body 14 so that the electrode body 30 is accommodated from the opening portion of the container body 13, and the joint between the lid body 14 and the container body 13 is, for example, Sealed by laser welding. In this way, the wound electrode body 30 is accommodated in the container 12.

  Next, as shown in FIG. 2, a predetermined amount of electrolyte E is injected into the container 12 from the electrolyte injection port 17 provided in the lid 14 (step S20 shown in FIG. 1). Typically, the injection (supply) of the electrolytic solution can be preferably performed in a vacuum chamber. The amount of electrolytic solution supplied into the container 12 is appropriately managed by, for example, detecting an increase in mass of the container 12 (containing the electrode body 30 and the supplied electrolytic solution E) due to the injection of the electrolytic solution E. Can do. When a predetermined amount of electrolyte is injected, an appropriate sealing member (not shown) is attached to the injection port 17 to seal the injection port 17. Thus, the battery assembly 20 in which the wound electrode body 30 and the electrolytic solution E are accommodated in the container 12 is obtained.

In addition, as said electrolyte solution, the thing similar to the nonaqueous electrolyte solution conventionally used for a lithium ion battery can be used without limitation. Such a nonaqueous electrolytic solution typically has a composition in which a supporting salt is contained in a suitable nonaqueous solvent. Examples of the non-aqueous solvent include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 1,3-dioxolane, and the like. One kind or two or more kinds selected from the group can be used. Moreover, as said support salt, the 1 type (s) or 2 or more types selected from the various lithium salt which can be melt | dissolved in the nonaqueous solvent to be used can be used, for example. For _example, LiPF _6, and _{LiBF 4, LiAsF 6, LiCF 3} SO 3, LiC 4 F 9 SO 3, LiN (CF 3 SO 2) 2, LiC (CF 3 SO 2) Fluorine constituent elements such as ₃ A lithium salt can be preferably used. In the lithium ion battery according to this embodiment, lithium hexafluorophosphate (LiPF ₆ ) as a supporting salt is contained in a mixed solvent of diethyl carbonate and ethylene carbonate (for example, a mass ratio of 1: 1) at a concentration of about 1 mol / liter. The electrolyte solution is used.

Here, since the wound electrode body 30 (in particular, the wound core portion 31) is generally wound with the positive electrode sheet 32, the negative electrode sheet 34, and the separator sheet, the electrolytic solution E is contained in the container 12 in step S20. Even if the electrolyte is injected, the electrolytic solution E does not immediately permeate the entire electrode body 30. That is, when the electrolytic solution E is injected into the container 12 in step S20, as shown in FIG. 3, the electrolytic solution E that has not yet penetrated into the electrode body 30 is accumulated outside the electrode body 30, and this electrolytic solution E is mainly used. It gradually permeates into the inside of the electrode body 30 from the axial end of the wound electrode body 30 (step S30 shown in FIG. 1). As the electrolyte solution E penetrates (permeates), the liquid level of the electrolyte solution (that is, the residual electrolyte solution) E outside the electrode body 30 gradually decreases. However, as shown in FIG. A part of E is held at a position higher than the liquid level. Therefore, as the penetration of the electrolytic solution E into the electrode body 30 proceeds, the position of the center of gravity of the assembly 20 moves upward of the assembly 20. Normally, the lower end of the electrode body 30 (the winding axis as in the present embodiment) is also in a state where the electrolyte E is properly distributed over the entire wound electrode body 30 (a target ideal electrolyte penetration state). In a battery in which the wound electrode body 30 is accommodated in the container 12 so as to lie down, a residual electrolyte solution that is soaked slightly that the lower end of the end in the winding axis direction remains slightly (for example, approximately 1 cm ³ to 10 cm ³ approximately, ^{3 cm} 3) in the present embodiment, it is preferable to set the electrolyte supply to the container 12 in step S20. According to such a configuration, since the residual electrolyte is replenished (sucked up) to the electrode body 30 as necessary, the state in which the electrolyte is properly distributed throughout the electrode body 30 is better maintained over a long period of time. can do.

  In the manufacturing method according to the present embodiment, after injecting the electrolyte E into the container 12 in step S20, the electrolyte E is infiltrated into the wound electrode body 30 over a predetermined time (step S30). Here, the time for which the electrolytic solution E is permeated is, for example, appropriately permeated into the entire electrode body 30 in the battery assembly 20 manufactured on the average based on the past manufacturing results and the results of preliminary experiments. It can be set as a time that allows a certain amount of margin (for example, about 1 hour) in consideration of the variation in a sufficient time (for example, about 4 hours). In the present embodiment, the electrolyte solution permeation time is 5 hours.

And after the said predetermined time passes since injection | pouring of the electrolyte solution E, the weight balance of the battery assembly 20 is measured (step S40 shown in FIG. 1), and the grade of the downward bias | inclination of this weight balance is grasped | ascertained. Thereby, the permeation | transmission state of the electrolyte solution E to the electrode body 30 is determined (step S50).
The degree of unevenness of the weight balance (that is, the permeation state of the electrolytic solution E) can be grasped using, for example, the electrolytic solution permeation state determination device 50 having a schematic configuration shown in FIG. In general, the device 50 includes a support portion 52 that supports the assembly 20 so that the lower portion of the battery assembly 20 can rotate with respect to the upper portion, and the supported assembly 20 resists gravity. And a measuring unit 62 configured to be able to measure a force to rotate from an inclined posture to a posture according to gravity.

The support portion 52 includes two arms 54 for holding the container 12 at two opposite sides of the side surface (here, a side surface perpendicular to the axial direction of the wound electrode body 30; see FIG. 5) 12A. The assembly 20 is supported by the support 52 so that the assembly 20 can rotate about a rotation axis R at a position where the tip of the arm 54 abuts on both side surfaces 12A of the container 12 as a fulcrum P.
Here, the position of the fulcrum P is determined when the assembly 20 is suspended between the fulcrum P by the arm 54 in a state in which the fulcrum P is rotatable about the rotation axis R. It is preferable to set the vertical position of the battery in the normal use state of the manufactured battery to a position where it does not reverse. Therefore, it is preferable to set the position of the fulcrum P so that the rotation axis R is above the position of the center of gravity of the assembly 20 when the assembly 20 is in the target infiltration state. Normally, as a guideline for setting the position of the fulcrum P, instead of the position of the center of gravity of the assembly 20 when the assembly 20 is in the target infiltration state, the assembly 20 when the electrolyte E is not injected is used. The position of the center of gravity can be used. In addition, since the position of the fulcrum P is set in a range higher than the center of gravity and lower than the upper end of the side surface 12A rather than the upper end of the side surface 12A of the container 12, the weight balance is biased. Some degree (related to some amount of residual electrolyte solution) can be detected with higher sensitivity. For example, the ratio between the distance D1 from the upper end of the side surface 12A of the container 12 to the fulcrum P and the distance D2 from the height of the center of gravity when the assembly 20 is in the target infiltration state on the side surface 12A ( D1: D2) can be in the range of approximately 9: 1 to 1: 9. Usually, this ratio (D1: D2) is preferably in the range of about 9: 1 to 5: 5. In the battery 10 according to this embodiment, the length of the side surface 12A of the container 12 is 90 mm, and the position of 40 mm from the upper end of the side surface 12A is supported by the arm 54 at the center in the width direction of the side surface 12A.

The measurement unit 62 includes a bottomed cylindrical holder 64, a measurement terminal 66 accommodated inside the holder 64 so as to be slidable in the axial direction of the holder 64, and a bottom portion of the holder 64 (the measurement terminal 66 and the holder). And a compression type load meter 68 installed between the bottom surface of 64. In this embodiment, as the load meter 68, a compression type load meter manufactured by Tokyo Sokki Kenkyujo Co., Ltd., model name “CLS-20NA” (capacity 20N) was used. The load meter 68 is connected to a data processing unit 72 that processes measurement data. For example, the data processing unit 72 is configured to be able to hold (store) a target value, which will be described later, compare the target value with a measured value, hold the comparison result, and output the comparison result. .
The measuring unit 62 has a posture in which the assembly 20 suspended at the fulcrum P follows the gravity (typically a posture in which the longitudinal direction of the side surface 12A of the container 12 substantially coincides with the vertical direction as shown in FIG. The measuring terminal 66 is positioned near the lower end of the wide surface (the widest surface) 12B of the container 12 and in the center of the wide surface 12B in the width direction (the axial direction of the wound electrode body 30). It is installed so that the tip of the abuts. Here, the angle at which the assembly 20 is tilted from the posture in accordance with the gravity is preferably a constant angle selected from the range of approximately 30 ° to 45 °. If this tilt angle is too large, tilting the assembly 20 may cause the residual electrolyte to move greatly within the container 12, thereby changing the permeation state of the electrolyte. That is, the operation itself for determining the infiltration state is not preferable because the state to be determined (that is, the infiltration state) can be changed. If the tilt angle is too small, the measurement value detected by the load meter 62 described later becomes small, and the measurement accuracy may tend to decrease. FIG. 8 shows an example in which the assembly 20 is configured to come into contact with the tip of the measurement terminal 66 in a posture inclined by 45 ° from the posture according to the gravity as a preferable example. At this time, it is preferable to arrange the measuring unit 62 so that the axial direction of the holder 64 (the sliding direction of the measurement terminal 66) is substantially perpendicular to the wide surface 12B of the container 12.

In this manner, the vicinity of the lower end of the wide surface 12B of the container 12 is locked to the tip of the measurement terminal 66 in a posture in which the assembly 20 is tilted against gravity, so that the tilted posture is rotated to a posture according to gravity. The force with which the assembly 20 to be pushed pushes the measurement terminal 66 by gravity is measured by a load meter 68. Here, as shown in FIG. 7, the electrolyte solution injected into the container 12 is not sufficiently permeated as shown in FIG. 7 compared to the assembly 20 in which the electrolyte solution is sufficiently infiltrated into the electrode body 30. In some assembly 20, the amount of residual electrolyte E is large. Since this residual electrolyte E accumulates on the lower side of the container 12, the measured value by the load meter 68 is larger in the assembly 20 shown in FIG. 7 than in the assembly 20 shown in FIG. FIG. 9 schematically shows the relationship between the amount of the residual electrolyte and the load (measured value by the load meter 68). FIG. 9 shows that in the assembly 20 having a larger amount of residual electrolyte as shown in FIG. 7 (the amount of electrolyte E penetrating into the electrode body 30 is insufficient), the amount of residual electrolyte is as shown in FIG. This shows that the load value measured is smaller than that of the assembly 20 that is less (the electrolyte solution E is better infiltrated into the electrode body 30). Using this relationship, the measured value is set to a preset target value (for example, the measured value of the load meter 68 obtained by using the battery assembly 20 in a state where the electrolytic solution sufficiently penetrates the electrode body 30). (In this embodiment, W0 = 0.08N), in other words, whether or not the amount of the residual electrolyte E is sufficiently reduced (for example, until 3 cm ³ or less). For example, it is determined whether or not the electrolytic solution E has sufficiently penetrated into the electrode body 30 (step S50 shown in FIG. 1).

That is, for the assembly 20 in which the measured value W1 by the load meter 68 is equal to or less than the target value W0 (W1 ≦ W0), it is determined that the penetration of the electrolytic solution into the electrode body 30 has sufficiently progressed (YES determination). . For the assembly 20 determined as YES, the permeation of the electrolytic solution is completed (step S60), and the process proceeds to a downstream process (for example, a conditioning process).
On the other hand, for the assembly 20 in which the measured value W1 measured by the load meter 68 is larger than the target value W0 (W1> W0), it is determined that the electrolyte solution has not sufficiently penetrated into the electrode body 30 (NO determination). . The assembly 20 determined to be NO is allowed to stand for a while to further permeate the electrolyte (return to step S30), and then the weight balance is measured again in the same manner as described above (step S40). As a result, when W1 ≦ W0 is achieved (YES determination), the process proceeds to a downstream process, and when W1> W0 still remains (NO determination), the process returns to step S30. Here, there is no decrease in the measured value compared to the previous measured value (meaning that the amount of residual electrolyte is not reduced, that is, no improvement is observed in the penetration of the electrolyte). May be excluded from the production line because it is determined that there is some factor that hinders the penetration of the electrolyte.
According to this embodiment, the penetration state of the electrolytic solution E into the wound electrode body 30 can be easily and accurately determined. Further, the lithium ion battery 10 in which the electrolytic solution E appropriately penetrates the wound electrode body 30 can be manufactured stably.

  As described above, the present invention has been described with reference to the preferred embodiments. However, such description is not a limitation, and various modifications can be made. For example, in the above-described embodiment, the winding electrode body is described as an example of a battery in which the winding axis is housed in a container in a posture in which the winding axis lies sideways. However, for example, the winding axis is vertically oriented (typically, You may apply this invention to the battery of the form accommodated in the container with the attitude | position which becomes the vertical direction in a normal use condition. The configuration of the electrode body is not limited to the wound type as described above, and may be a laminated type electrode body (laminated electrode body) formed by alternately laminating positive electrode sheets and negative electrode sheets together with separator sheets, for example. The type of battery is not limited to the lithium ion battery described above, but various batteries having different electrode body constituent materials and electrolyte compositions, such as a lithium secondary battery, a nickel metal hydride battery, and a nickel cadmium battery having lithium metal or a lithium alloy as a negative electrode. Alternatively, an electric double layer capacitor (physical battery) may be used.

Further, in the above embodiment, as shown in FIG. 8, the measurement value detected by pressing the load meter 68 when the battery assembly 20 held in a tilted posture against gravity is rotated according to the gravity. Although the degree of the downward bias of the weight balance of the assembly 20 is grasped using (load) as an index, the method of grasping the degree of the weight balance bias is not limited to this. For example, as shown in FIG. 5, the assembly 20 is suspended in a posture according to gravity, and a force (moment of inertia) required to shift the assembly 20 to a tilted posture against gravity is detected. Thus, it may be configured to grasp the degree of the weight balance deviation.
Further, the technology disclosed herein is preferably used in the manufacturing process of a battery (typically a secondary battery), and is also preferably used as a method for determining the electrolyte penetration state of a completed battery (product). be able to.

It is a flowchart which shows the principal part of the battery manufacturing method which concerns on one Embodiment. It is explanatory drawing which shows typically the process of inject | pouring electrolyte solution into a container. It is explanatory drawing which shows typically the process of making an electrolyte body osmose | permeate an electrode body. It is explanatory drawing which shows typically the process of making an electrolyte body osmose | permeate an electrode body. It is explanatory drawing which shows typically the determination method of an electrolyte solution osmosis | permeation state. It is explanatory drawing which shows typically the determination method of an electrolyte solution osmosis | permeation state. It is explanatory drawing which shows typically the determination method of an electrolyte solution osmosis | permeation state. It is explanatory drawing which shows typically schematic structure of the electrolyte solution penetration state determination apparatus which concerns on one Embodiment. It is explanatory drawing which shows typically the relationship between the load measured and the amount of residual electrolyte solution. It is a side view which shows typically the vehicle (automobile) provided with the secondary battery (lithium ion battery) which concerns on one Embodiment.

Explanation of symbols

1 Vehicle (Automobile)
10 Lithium ion battery (secondary battery)
12 Container 12A Side 17 Inlet 20 Battery assembly 30 Winding electrode body 50 Penetration state measuring device 52 Support part 54 Arm 62 Measuring part 68 Load cell

Claims (10)

A process of constructing a battery assembly by accommodating an electrode body in a form in which sheet-like electrodes are superimposed and an electrolyte solution in a container;
Immersing the electrode body in the electrolytic solution to infiltrate the electrolytic body into the electrode body;
Grasping the degree of deviation of the weight balance of the assembly downward in the vertical direction;
Comparing the degree of bias with a preset target value;
With
Here, when the degree of bias is less than or equal to the target value, it is determined that the electrolyte has sufficiently penetrated and the process proceeds to a downstream process, and the degree of bias is greater than the target value. In the secondary battery manufacturing method, it is determined that the electrolyte solution is insufficiently permeated and the shift to the downstream process is suspended.   The assembly is supported so that the lower part of the assembly can rotate with respect to the upper part, the assembly is held in a tilted position against gravity, and the assembly takes a position according to gravity. The method of manufacturing a secondary battery according to claim 1, wherein the degree of bias of the weight balance is grasped by measuring a moment force generated by trying to rotate.   The secondary battery manufacturing method according to claim 2, wherein the posture tilted against the gravity is a posture tilted by 30 ° to 45 ° from a posture according to the gravity.   The method of manufacturing a secondary battery according to claim 2 or 3, wherein the assembly is supported by using two opposing portions of the assembly as fulcrums.   The secondary electrode manufacturing method according to any one of claims 1 to 4, wherein the electrode body is a wound electrode body in which the stacked sheet-like electrodes are wound in a longitudinal direction. A battery assembly having a configuration in which an electrode body and an electrolyte solution in a form in which sheet-like electrodes are superimposed are contained in a container, a method for determining a permeation state of the electrolyte solution into the electrode body,
Grasping the degree of deviation of the weight balance of the assembly downward in the vertical direction;
Comparing the degree of bias with a preset target value;
If the degree of bias is less than or equal to the target value, it is determined that the electrolyte solution has sufficiently penetrated. If the degree of bias is greater than the target value, the electrolyte solution is not sufficiently penetrated. A step of determining
An electrolyte solution permeation state determination method comprising:   The assembly is supported so that the lower part of the assembly can rotate with respect to the upper part, the assembly is held in an inclined position against gravity, and the assembly is in a position according to gravity. The electrolyte solution penetration state determination method according to claim 6, wherein the degree of deviation of the weight balance is grasped by measuring a moment force generated by trying to rotate. A battery assembly having a configuration in which an electrode body and an electrolytic solution are housed in a container, and a device for determining a permeation state of the electrolytic solution into the electrode body,
A support for supporting the assembly so that the lower portion of the assembly can rotate relative to the upper portion;
A measurement unit for measuring a moment force generated when the supported assembly is rotated to take a posture according to gravity from a posture inclined against gravity;
An electrolyte infiltration state determination device comprising:   The apparatus according to claim 8, wherein the measurement unit is arranged at a position that prevents the assembly from rotating from a posture inclined against gravity to a posture according to gravity.   A vehicle comprising a secondary battery manufactured by the method according to any one of claims 1 to 5.

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