JP2017174617A - Method of manufacturing lithium ion secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a lithium ion secondary battery capable of appropriately processing metal foreign matters mixed into the inside of a battery case and capable of processing the metal foreign matters in a short time.SOLUTION: A method of manufacturing a lithium ion secondary battery according to the present invention includes a foreign matter treatment process in which metal foreign matters mixed into the inside of a battery case is processed by adjusting a positive electrode potential to a dissolution potential of predetermined metal foreign matters. Further, the foreign matter treatment process includes: a first step of, from the outside of the battery case, applying a compression load in a lamination direction of an electrode body and heating the battery case; and a second step of lowering the compression load on the battery case than that in the first step and lowering battery temperature than that in the first step.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for manufacturing a lithium ion secondary battery.

  Generally, a lithium ion secondary battery contains an electrode body in which a positive electrode plate and a negative electrode plate are laminated and an electrolytic solution inside a battery case. And in the manufacturing process of a lithium ion secondary battery, a metal foreign material may mix in a battery case inside.

  For example, a battery case of a lithium ion secondary battery may be composed of two parts, a case main body in which an opening is formed and a lid member that closes the opening of the case main body. In such a case, the case body may be welded by closing the opening of the case body with a lid and joining these two parts. During welding of the battery case, spatter scattered during welding may become a metal foreign matter and enter the battery case.

  And when a metal foreign material has mixed in the inside of a battery case, it is preferable to process a metal foreign material appropriately. This is because if the metal foreign matter remains inside the battery case as it is, it may cause a problem such as an internal short circuit of the lithium ion secondary battery.

  For example, Patent Document 1 describes that a positive electrode potential is held for a predetermined time as a dissolution potential of a metal foreign object while applying a compression load in the electrode body stacking direction from the outside of the battery case. Thereby, the positive electrode plate and the metal foreign object are brought into contact with each other, and the metal foreign object is set to the dissolution potential, and the metal foreign object can be appropriately dissolved and diffused.

Japanese Patent No. 5348139

  By the way, it is preferable that the metal ions generated by the dissolution of the metal foreign matter are appropriately diffused after the metal foreign matter mixed in the battery case is dissolved. Metal ions tend to move to the negative electrode side during charging and precipitate as metal on the negative electrode. For this reason, when metal ions are not properly diffused and there are locations where the concentration of metal ions is high, there is a risk that metal deposition will be concentrated near the locations where the concentration of metal ions is high. is there. That is, if the metal ions are not properly diffused, metal deposits derived from the metal foreign matter may be locally generated.

  However, the above-described conventional technique has a problem that it takes a long time to appropriately dissolve and diffuse the metal foreign matter. That is, diffusion of metal ions is difficult to occur simply by dissolving metal foreign matter. For this reason, it takes time until the metal ion concentration around the portion where the metal foreign matter is mixed decreases.

  The present invention has been made for the purpose of solving the problems of the prior art described above. That is, the problem is to provide a method of manufacturing a lithium ion secondary battery that can appropriately handle the metal foreign matter mixed in the battery case and can process the metal foreign matter in a short time. .

  The method of manufacturing a lithium ion secondary battery of the present invention, which has been made for the purpose of solving this problem, includes an electrode body in which a positive electrode plate and a negative electrode plate are laminated with a separator interposed therebetween, and the electrode body together with an electrolyte. A battery case housed inside, a positive electrode terminal and a negative electrode terminal provided on the battery case, one end side of which is connected to the electrode body inside the battery case and the other end side exposed to the outside of the battery case. A method of manufacturing a lithium ion secondary battery comprising: a housing step of housing an electrode body and an electrolyte solution in a battery case; and metal foreign matter mixed in the battery case, dissolution of metal foreign matter having a predetermined positive electrode potential A foreign matter treatment process that treats the substrate by applying an electric potential. The foreign matter treatment step applies a pressing load in the stacking direction of the electrode body from the outside of the battery case and heats the battery case. A lithium ion secondary comprising: a first step; and a second step of lowering the pressure load on the battery case than that of the first step and lowering the battery temperature than that of the first step. It is a manufacturing method of a battery.

  In this method of manufacturing a lithium ion secondary battery, the electrolytic solution in the electrode body can be moved by the first step and the second step. By the movement of the electrolytic solution, metal ions generated by the dissolution of the metal foreign matter can be diffused. Thereby, it can prevent that the location where the density | concentration of the metal ion which concerns on a metal foreign material has a high density | concentration does not arise in electrolyte solution, and can suppress that a metal ion precipitates as a metal. Moreover, by moving the electrolyte in the electrode body in the first step and the second step, it is possible to promote the diffusion of metal ions generated by the dissolution of the metal foreign matter. For this reason, the foreign substance processing step can be completed in a short time. Therefore, the metal foreign matter mixed in the battery case can be appropriately treated, and the metal foreign matter can be processed in a short time.

In the method for manufacturing a lithium ion secondary battery described above, the battery case has a rectangular space surrounded by the inner wall surface, and the positive electrode is connected to the first inner wall surface which is one of the inner wall surfaces. In addition to the terminal and the negative terminal, a processing terminal that is at least partially exposed in the battery case and is not electrically connected to the electrode body is provided. Both the positive terminal and the processing terminal are viewed from the negative terminal. The foreign matter processing step is performed after the first step and the second step, and the posture of the battery case is changed to the first inner wall surface. While making the lower side in the vertical direction, the positive electrode terminal is inclined in a direction that is lower in the vertical direction than the negative electrode terminal, and the angle θ between the first inner wall surface and the horizontal plane in the inclination is expressed by the following equation:
θ ≦ tan ⁻¹ [V / {A ² (BC)}]
V: Volume of electrolytic solution A: Distance from the first side of the first inner wall surface to the farthest distance from the first side of the positive terminal and the processing terminal B: Length of the first side C: It is preferable to have a third step of holding for a predetermined time as a posture satisfying the length of the electrode body in the direction of the first side. In the third step, metal ions generated by the dissolution of the metal foreign matter can be deposited on the processing terminal as metal. Thereby, the metal ion produced by melt | dissolution of a metal foreign material can be removed from electrolyte solution. Therefore, it is possible to suppress the metal ions generated by the dissolution of the metal foreign matter from being deposited as metal on the negative electrode plate or the like after the foreign matter treatment step.

In the method of manufacturing a lithium ion secondary battery described above, in the third step, the orientation of the battery case is expressed by the angle θ,
θ> tan ⁻¹ [V / {D ² (BC)}]
D: It is preferable that the posture satisfies the distance from the first side on the first inner wall surface to the negative electrode terminal. By making the battery case posture so that the negative electrode terminal does not immerse in the electrolyte, it is possible to prevent metal ions in the electrolyte produced by dissolution of metal foreign matter from being deposited on the negative electrode as metal. Because. And since the metal precipitation in a negative electrode can be prevented, the fine short circuit which arises by metal precipitation can be prevented. Furthermore, since the metal deposition in the negative electrode can be prevented, the decrease in the exposed surface area of the negative electrode accompanying the metal deposition can be prevented, so that the decrease in battery capacity can also be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, while manufacturing the metal foreign material mixed inside the battery case appropriately, the manufacturing method of the lithium ion secondary battery which can process the metal foreign material in a short time is provided.

It is a perspective view of the battery which concerns on a 1st form. It is sectional drawing of the positive electrode plate etc. which comprise an electrode body. It is a flowchart which shows the procedure of the manufacturing process of a battery. It is a flowchart which shows the procedure in the foreign material processing process which concerns on a 1st form. It is a schematic block diagram of the restraint temperature adjustment apparatus used in a compression heating process and a release cooling process. It is sectional drawing of the mixing location of the metal foreign material of an electrode body. It is a graph which shows the relationship between the thickness of an electrode body, and a restraint pressure. It is a graph which shows the relationship between the temperature of electrolyte solution, and a viscosity. It is a perspective view of the battery which concerns on a 2nd form. It is a flowchart which shows the procedure in the foreign material processing process which concerns on a 2nd form. It is a figure which shows the inclination attitude | position of the battery case in an inclination holding process. It is XX sectional drawing in FIG. It is a figure which shows transition of the battery voltage of the battery of an Example and a comparative example. It is a figure which shows transition of the capacity | capacitance maintenance factor of the battery of an Example and a comparative example.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best mode for embodying the present invention will be described in detail with reference to the drawings.

[First embodiment]
First, a lithium ion secondary battery manufactured by the manufacturing method of this embodiment will be described. FIG. 1 is a perspective view of a battery 100 according to this embodiment. As shown in FIG. 1, the battery 100 is configured by housing an electrode body 120 and an electrolytic solution 130 inside a battery case 110.

The electrolytic solution 130 is a non-aqueous electrolytic solution made of an organic solvent in which a lithium salt is dissolved. Specifically, the electrolytic solution 130 of the present embodiment uses a mixed solvent obtained by mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in the following volume ratio as an organic solvent. .
EC: 3
EMC: 3
DMC: 4

Moreover, the electrolyte solution 130 of this embodiment uses lithium hexafluorophosphate represented by the chemical formula LiPF ₆ as the lithium salt. The electrolytic solution 130 is obtained by adding the above lithium salt to the above mixed solvent so that the lithium ion has a concentration of 1.1 mol / l.

  The battery case 110 includes a case main body 111 having an opening formed on the upper side in the height direction, and a sealing plate 112 closing the opening of the case main body 111. The battery case 110 of this embodiment has a flat shape with a rectangular outer shape. For this reason, the internal space of the battery case 110 surrounded by the inner wall surface of the battery case 110 is also rectangular.

  The sealing plate 112 is provided with a positive terminal 140 and a negative terminal 150. The positive electrode terminal 140 and the negative electrode terminal 150 are respectively provided near one end side and the other end side in the width direction of the battery case 110. Further, the sealing plate 112 is formed with a liquid injection port 113 for injecting the electrolytic solution 130 into the battery case 110. The liquid injection port 113 is sealed with a sealing member 115 after the electrolyte solution 130 is injected.

  As shown in FIG. 1, the electrode body 120 of this embodiment is a flat wound type. FIG. 2 shows a cross-sectional view of the positive electrode plate 160, the negative electrode plate 170, and the separator 180 that constitute the electrode body 120. 1 has a positive electrode plate 160, a negative electrode plate 170, and two separators 180 overlapped as shown in FIG. 2, and wound in a cylindrical shape with the horizontal direction in FIG. 2 as the direction of the winding axis. After that, the wound body was formed into a flat shape by pressing in the radial direction.

  As the separator 180, for example, a porous sheet such as polypropylene (PP) or polyethylene (PE) can be used alone. A composite material formed by laminating a plurality of porous sheets of different materials can also be used as the separator 180.

  The positive electrode plate 160 is formed by forming a positive electrode active material layer 162 on both surfaces of a positive electrode current collector foil 161 using a positive electrode material such as a positive electrode active material or a binder. The positive electrode plate 160 has a portion where the positive electrode active material layer 162 is formed and a portion where the positive electrode active material layer 162 is not formed and the positive electrode current collector foil 161 is exposed.

  The negative electrode plate 170 is formed by forming a negative electrode active material layer 172 on both surfaces of a negative electrode current collector foil 171 using a negative electrode material such as a negative electrode active material or a binder. The negative electrode plate 170 has a portion where the negative electrode active material layer 172 is formed and a portion where the negative electrode active material layer 172 is not formed and the negative electrode current collector foil 171 is exposed.

  As shown in FIG. 2, both the negative electrode plate 170 and the positive electrode plate 160 are overlapped with the separator 180 in the portion where the respective positive electrode active material layer 162 and the negative electrode active material layer 172 are formed. Therefore, the central portion 121 of the electrode body 120 shown in FIG. 1 is a portion in which the positive electrode plate 160, the negative electrode plate 170, and the separator 180 are laminated. The stacking direction of the positive electrode plate 160 and the like in the electrode body 120 is the same as the thickness direction of the battery case 110.

  On the other hand, as shown in FIG. 2, the exposed portion of the positive electrode current collector foil 161 of the positive electrode plate 160 and the exposed portion of the negative electrode current collector foil 171 of the negative electrode plate 170 have one end side and the other end in the width direction from the separator 180. Each projecting to the side. For this reason, the positive electrode end portion 122 of the electrode body 120 shown in FIG. 1 is a portion composed only of the exposed portion of the positive electrode current collector foil 161 of the positive electrode plate 160. Further, the negative electrode end portion 123 of the electrode body 120 is a portion composed only of an exposed portion of the negative electrode current collector foil 171 of the negative electrode plate 170.

  In the battery 100 shown in FIG. 2, the positive electrode terminal 140 of the electrode body 120 is connected to the positive electrode terminal 140, and the negative electrode terminal 123 is connected to the negative electrode terminal 150. Further, the positive electrode terminal 140 and the negative electrode terminal 150 have their ends not connected to the electrode body 120 protruding outside the battery case 110.

  Further, the battery 100 is charged and discharged at the central portion 121 of the electrode body 120 via the positive electrode terminal 140 and the negative electrode terminal 150. Specifically, the battery 100 is held in the pores of the separator 180, which is a porous member, between the positive electrode plate 160 and the negative electrode plate 170 located at the central portion 121 of the electrode body 120 during charging and discharging. Lithium ions are exchanged through the electrolytic solution 130.

  Next, a method for manufacturing the battery 100 of this embodiment will be described. FIG. 3 is a flowchart showing the procedure of the manufacturing process of the battery 100. That is, as shown in FIG. 3, the battery 100 is manufactured by the accommodation process (S10) and the foreign substance processing process (S11).

  First, in the housing step (S10), the electrode body 120 is housed inside the case body 111 through the opening. As described above, the electrode body 120 is manufactured by winding the positive electrode plate 160, the negative electrode plate 170, and the two separators 180 into a cylindrical shape, and then pressing them in the radial direction. Further, the superposition of the positive electrode plate 160, the negative electrode plate 170, and the separator 180 in winding is as described with reference to FIG.

  Further, in the housing process, the opening of the case body 111 is closed by the sealing plate 112 and these are joined. The positive electrode terminal 140 and the negative electrode terminal 150 may be connected to the electrode body 120 before the electrode body 120 is accommodated in the case body 111. The joining of the battery case 110 and the joining of the positive electrode terminal 140 and the negative electrode terminal 150 to the electrode body 120 can be performed by welding or the like.

  Further, in the housing process, the electrolytic solution 130 is also housed inside the battery case 110. The electrolytic solution 130 can be injected into the battery case 110 from the liquid injection port 113 formed in the sealing plate 112 of the battery case 110. The injection port 113 may be closed by the sealing member 115 after the electrolyte solution 130 is injected. The battery 100 shown in FIG. 1 is configured by this housing process.

  Next, a foreign substance processing step (S11) is performed. The foreign matter processing step is a step for processing metal foreign matter that has been mixed in the battery case 110 before the containing step. For example, the metal foreign matter may be generated during welding of the battery case 110 in the housing process and mixed into the battery case 110.

  FIG. 4 is a flowchart showing a procedure in the foreign matter processing step of the present embodiment. That is, as shown in FIG. 4, in the foreign substance processing step, a potential adjustment step (S20), a compression heating step (S21), and a release cooling step (S22) are performed.

  First, in the potential adjustment step (S20), the potential of the positive electrode of the battery 100 is adjusted. That is, in the potential adjustment step, the potential of the positive electrode is set as the dissolution potential of the metal foreign matter. The dissolution potential of the metal foreign object is an oxidation potential of the metal and is a potential at which the metal foreign object is dissolved. For example, when iron is used as the object of the metal foreign matter to be dissolved, the potential of the positive electrode is set to about 2.5 V (vs. Li / Li +) or more, which is the dissolution potential of iron. Further, when a plurality of metals are included as objects of the metal foreign matter to be dissolved, the potential of the positive electrode may be adjusted to the melting potential of the metal having the highest dissolution potential.

  Next, the compression heating process (S21) is performed on the battery 100 in which the positive electrode potential is adjusted to the dissolution potential of the metal foreign matter. FIG. 5 shows the restraint temperature adjusting device 1 used in the compression heating process. As shown in FIG. 5, the restraint temperature adjustment device 1 includes a pressure plate 2, a temperature adjustment unit 3, a compression unit 4, and a guide unit 5.

  The temperature adjustment part 3 is a plate-like thing which can adjust the temperature to high temperature or low temperature. The pressure plates 2 are provided on both surfaces of the temperature adjusting unit 3 in the thickness direction. The compression part 4 can slide the pressure plate 2 and the temperature adjustment part 3 along the guide part 5 in the thickness direction thereof. The compression unit 4 can sandwich the pressure plate 2 and the temperature adjustment unit 3 from both sides in the thickness direction, and can adjust the restraining force due to the sandwiching.

  In the compression heating process, the battery 100 is inserted between the pressure plates 2 of the restraint temperature adjusting device 1. The battery 100 is inserted into the restraint temperature adjusting device 1 such that the thickness direction thereof, that is, the stacking direction of the electrode bodies 120 is aligned with the direction of sliding by the compression unit 4. In FIG. 4, three batteries 100 are inserted into the restraint temperature adjusting device 1.

  Furthermore, the restraint temperature adjusting device 1 restrains the battery 100 in the thickness direction and heats it. Specifically, after the battery 100 is inserted between the pressure plates 2, the battery 100 is sandwiched between the compression parts 4, and a compression load is applied in the thickness direction from the outside of the battery case 110. Thereby, a pressing load in the stacking direction is applied to the electrode body 120 in the battery case 110.

  In the compression heating process, the battery 100 is restrained and the temperature of the temperature adjusting unit 3 is adjusted to a high temperature. The battery 100 is heated via the pressure plate 2 by adjusting the temperature of the temperature adjustment unit 3 to a high temperature. Thereby, the electrode body 120 in the battery case 110 is also heated. The compression heating process is performed for a predetermined time.

  Furthermore, as shown in FIG. 4, a release cooling process (S22) is performed following the compression heating process (S21). The restraint temperature adjusting device 1 can also be used in the release cooling process. In the release cooling process, the restraining force by the compression unit 4 is weaker than that in the compression heating process, and the compression load applied to the battery 100 is reduced. Thereby, the compression load applied to the electrode body 120 is also reduced. Specifically, in this embodiment, the compression unit 4 is moved to a place where the battery 100 does not receive a compression load. Thereby, in the release cooling process of this embodiment, the electrode body 120 is released from the compression.

  In the release cooling process, the binding force of the battery 100 is weakened and the temperature of the temperature adjustment unit 3 is adjusted to a low temperature. The battery 100 is cooled via the pressure plate 2 by adjusting the temperature of the temperature adjusting unit 3 to a low temperature. That is, in the release cooling process, the battery temperature of the battery 100 is lowered as compared with the compression heating process. Thereby, in the open cooling process, the temperature of the electrode body 120 is also lowered than in the compression heating process. The release cooling process is also performed for a predetermined time.

  In this embodiment, the compression heating step (S21) and the release cooling step (S22) are alternately repeated a plurality of times. Specifically, in this embodiment, as shown in FIG. 4, the compression heating step (S21) and the release cooling step (S22) are performed ten times in this order (S23). Then, the pressure heating step (S21) and the release cooling step (S22) are alternately repeated 10 times, and then the foreign matter processing step (S11) is ended.

  Here, in the foreign matter processing step of this embodiment, as described above, the compression heating step and the release cooling step are performed with the positive electrode potential adjusted to the dissolution potential of the metallic foreign matter. Thereby, the metal foreign material mixed in the battery case 110 before the accommodation process can be appropriately processed. This will be described.

  First, in the foreign matter processing step, as described above, the positive electrode potential is adjusted to the dissolution potential of the metallic foreign matter by the potential adjustment step. For this reason, as shown in FIG. 6, the metallic foreign matter M present on the surface of the positive electrode plate 160 in the electrode body 120 is eluted into the electrolytic solution 130. Since the metal ion Mi formed by dissolving the metal foreign matter M is a cation, it moves toward the negative electrode plate 170.

  In the compression heating process, a compression load is applied in the stacking direction of the electrode body 120, so that a gap between constituent members such as the positive electrode plate 160 in the electrode body 120 is narrowed. For this reason, the metal foreign matter M on the surface of the positive electrode plate 160 can be brought into contact with the positive electrode plate 160 more reliably. Further, the contact area between the metal foreign matter M and the positive electrode plate 160 can be increased. Therefore, in the compression heating process, the metal foreign matter M can be reliably brought to the dissolution potential by the compression of the electrode body 120. In the compression heating process, the electrode body 120 is heated. Thereby, the melt | dissolution reaction of the metal foreign material M can be accelerated | stimulated in a compression heating process.

  Further, in the compression heating process, the electrolytic solution 130 is discharged from the electrode body 120 that is subjected to a compression load in the stacking direction. This is because the gap between the constituent members of the electrode body 120 is narrowed. The electrolytic solution 130 moves in the pressed electrode body 120 along the positive electrode plate 160 and the like, and is discharged from the end of the electrode body 120 in the width direction. Further, in the compression heating process, the volume of the heated electrolyte 130 increases. Thereby, in the compression heating process, the amount of the electrolyte solution 130 discharged from the electrode body 120 is made larger than that when the electrode body 120 is not heated.

  Next, in the release cooling process, the electrode body 120 released from the compression expands in the stacking direction more than in the compression heating process due to the elastic force of the constituent members such as the positive electrode plate 160. Thereby, the clearance gap between the constituent members in the electrode body 120 that has been narrowed becomes large. When the gap in the electrode body 120 that has become narrower becomes larger, the electrolytic solution 130 flows into the electrode body 120 from the end in the width direction of the electrode body 120 into the gap that becomes larger. In the open cooling process, the volume of the cooled electrolyte 130 is reduced. Thereby, in the release cooling process, the amount of the electrolyte solution 130 flowing into the electrode body 120 is made larger than that when it is not cooled.

  That is, the electrolytic solution 130 in the electrode body 120 can be moved by performing the compression heating process and the release cooling process. As the electrolytic solution 130 moves, the metal ions Mi eluted from the metal foreign matter M can also be moved. That is, the diffusion of the metal ions Mi eluted from the metal foreign matter M can be promoted by performing the compression heating process and the release cooling process.

  Thereby, in the foreign substance processing process of this embodiment, the location where the density | concentration of metal ion Mi is high is not produced. Therefore, it can suppress appropriately that metal ion Mi deposits locally as a metal. Furthermore, as described above, in the foreign matter processing step of this embodiment, dissolution and diffusion of the metallic foreign matter M can be promoted. Thereby, in this embodiment, the foreign substance processing process which can process the metal foreign substance M appropriately can be completed in a short time.

  In the foreign matter processing step of this embodiment, it is not necessary to completely dissolve the mixed metal foreign matter. Specifically, in the foreign matter processing step of the present embodiment, the metal foreign matter may be dissolved until the particle size becomes 50 μm or less. That is, the residual metal foreign matter that is not completely dissolved in the foreign matter treatment process and remains after the foreign matter treatment step is dissolved in the normal use of the battery 100 thereafter. However, in this embodiment, metal ions in the electrolyte solution 130 around the residual metal foreign matter are diffused in the foreign matter treatment step. For this reason, even if residual metal foreign matter having a particle size of 50 μm or less is dissolved during normal use of battery 100, metal is deposited on negative electrode plate 170 so that the concentration of metal ions around the residual metal foreign matter causes an internal short circuit. It is because it is suppressed to such an extent that it does not occur.

  Therefore, each condition of the potential adjustment process, the pressure heating process, and the release cooling process in the foreign substance processing process may be determined so that the metal foreign substance having a size that is expected to be mixed can be reduced to at least a particle size of 50 μm or less. In other words, the positive electrode potential adjusted in the potential adjustment process, the compression load and heating temperature in the compression heating process, the cooling temperature in the release cooling process, the number of compression heating processes and the number of release cooling processes, etc. Experiments using metallic foreign objects can be performed in advance. It should be noted that each condition of the potential adjustment process, the pressure heating process, and the release cooling process in the foreign substance treatment process is, as a matter of course, capable of completely dissolving a metal foreign substance having a size that is expected to be mixed, and reliably diffusing the metal ions. Also good.

  In the potential adjustment step, it is preferable to adjust the potential of the positive electrode to a potential lower than the decomposition potential of the electrolytic solution 130. This is because when the potential of the positive electrode is increased to the decomposition potential of the electrolytic solution 130, the electrolytic solution 130 may be decomposed on the positive electrode surface that has reached the decomposition potential.

  In the compression heating process, it is preferable that the compression load applied to the battery case 110 in the stacking direction of the electrode body 120 is 0.1 MPa or less. FIG. 7 is a graph showing the relationship between the thickness of the electrode body 120 and the restraint pressure obtained by changing the restraint pressure while restraining the electrode body 120 in the stacking direction.

  As shown in FIG. 7, it can be seen that the thickness of the electrode body 120 becomes thinner as the restraining pressure is increased. Further, it can be seen that the ratio of the increase amount of the restraint pressure to the decrease amount of the thickness of the electrode body 120 is small in the range where the restraint pressure is 0.1 MPa or less. On the other hand, in the range where the restraint pressure is higher than 0.1 MPa, it can be seen that the ratio of the increase amount of the restraint pressure to the decrease amount of the thickness of the electrode body 120 is large.

  This is considered to be because the gap between the constituent members in the electrode body 120 is almost eliminated when the restraint pressure is about 0.1 MPa. That is, when the restraint pressure is in the range of 0.1 MPa or less, the gap between the constituent members in the electrode body 120 decreases as the restraint pressure increases, and the thickness of the electrode body 120 decreases. On the other hand, in the range where the restraint pressure is higher than 0.1 MPa, the gap between the constituent members in the electrode body 120 is almost eliminated, and even if the restraint pressure is higher than 0.1 MPa, It is considered that the gap cannot be reduced so much. That is, even if the compression load applied to the electrode body 120 is higher than 0.1 MPa as the pressure, it is considered that the effect of promoting the elution of the metallic foreign matter cannot be increased so much.

  Furthermore, the decrease in the thickness of the electrode body 120 in the range where the restraint pressure is higher than 0.2 MPa is considered to be due to the elastic deformation of the constituent members of the electrode body 120 in the stacking direction. That is, the higher the pressure load applied to the electrode body 120, the higher the risk that the separator 180 and the like will be damaged.

  Therefore, in the compression heating process, the pressure load on the battery case 110 is set to 0.1 MPa or less, thereby suppressing the damage to the electrode body 120 and appropriately reducing the gap between the constituent members, thereby preventing the metal foreign matter. Elution can be promoted.

  In the compression heating process, it is preferable that the heating temperature is lower than the decomposition temperature of the electrolytic solution 130. This is because when the temperature of the electrolytic solution 130 rises to the decomposition temperature, the electrolytic solution 130 is decomposed. Specifically, in this embodiment, it is preferable that the heating temperature in the compression heating step is less than 60 ° C.

  Further, in the release cooling process, it is preferable to restrain the battery case 110 to such an extent that the electrode body 120 is not deformed so that the position of the battery 100 inserted in the restraint temperature adjusting device 1 is not shifted. Such a compression load can be set to about 0.01 to 0.05 MPa as a pressure.

  In the open cooling step, the battery temperature is preferably higher than the viscosity increase point of the electrolytic solution 130. The viscosity increase point is determined at a temperature at which the ratio of the amount of change in viscosity to the amount of change in temperature of the electrolytic solution 130 whose viscosity increases as the temperature decreases changes greatly. FIG. 8 is a graph showing the relationship between the temperature and the viscosity of the electrolytic solution 130 obtained by changing the temperature of the electrolytic solution 130 of the present embodiment.

  As shown in FIG. 8, it can be seen that the viscosity increases as the temperature of the electrolytic solution 130 decreases. It can also be seen that in the electrolyte solution 130, the amount of change in viscosity with respect to the amount of change in temperature is greatly different at −10 ° C. as a boundary. That is, in the range of −10 ° C. or higher, the viscosity does not change so much even if the temperature changes. On the other hand, in the range below −10 ° C., the viscosity changes greatly with the change of temperature. That is, for the electrolytic solution 130, the viscosity increase point can be set to less than −10 ° C.

  Therefore, in the release cooling process of this embodiment, the battery temperature is preferably set to a temperature of −10 ° C. or higher. This is because the viscosity of the electrolytic solution 130 can be kept low and the electrolytic solution 130 can be appropriately flowed into the electrode body 120.

[Second form]
Next, the second embodiment will be described. Also in this embodiment, a lithium ion secondary battery is manufactured by a housing process and a foreign substance processing process, as in the first embodiment. However, in this embodiment, the configuration of the lithium ion secondary battery is partly different from the first embodiment. Further, in the present embodiment, unlike the first embodiment, in the foreign matter processing step, a step of removing metal ions related to the dissolved metal foreign matter from the electrolytic solution is performed.

  FIG. 9 shows a perspective view of a battery 200 according to this embodiment. As shown in FIG. 9, the battery 200 of this embodiment has a processing terminal 210 in addition to the positive terminal 140 and the negative terminal 150. However, unlike the positive terminal 140 and the negative terminal 150, the processing terminal 210 is not electrically connected to the electrode body 120, as shown in FIG. Similarly to the positive terminal 140 and the negative terminal 150, the processing terminal 210 is also provided on the sealing plate 112 of the battery case 110.

  As a material of the processing terminal 210, lithium metal, platinum, or the like can be used. In addition, a surface of the processing terminal 210 exposed inside the battery case 110 is a processing surface 211. The battery 200 of the present embodiment has the same configuration as that of the battery 100 of the first embodiment except that the processing terminal 210 is provided. Further, the material of each component of the battery 200 is the same as that of the battery 100 of the first embodiment.

  Also in this embodiment, the battery 200 is manufactured by the housing step (S10) and the foreign matter processing step (S11) shown in FIG. Among these, the accommodation step can be performed in the same manner as in the first embodiment. That is, in the housing process of this embodiment, the sealing plate 112 having the processing terminal 210 already assembled may be used. In this embodiment, the foreign substance processing step is performed by a procedure different from that of the first embodiment.

  FIG. 10 is a flowchart showing a procedure in the foreign matter processing step of the present embodiment. That is, as shown in FIG. 10, in the foreign substance processing step of this embodiment, the potential adjustment step (S30), the compression heating step (S31), the release cooling step (S32), and the tilt holding step (S34) are performed. Among these, the potential adjustment step (S30), the compression heating step (S31), and the release cooling step (S32) are the same as in the first embodiment.

  That is, also in the present embodiment, the compression heating step (S31) and the release cooling step (S32) are performed 10 times in this order for the battery 200 in which the positive electrode potential is adjusted to the dissolution potential of the metal foreign matter by the potential adjustment step (S30). Perform (S33). In this embodiment, the compression heating process (S31) and the release cooling process (S32) are alternately repeated 10 times, and then the tilt holding process (S34) is performed.

  In the tilt holding step, the battery 200 is held as a tilted posture tilted as shown in FIG. 11 for a predetermined time. In FIG. 11, a region surrounded by the opening of the case main body 111 in the surface located on the case main body 111 side of the sealing plate 112 is defined as a first inner wall surface 116. That is, the first inner wall surface 116 is one of the inner wall surfaces that form a rectangular internal space in the battery case 110.

  In the inclined position, the battery case 110 has the sealing plate 112 directed downward in the vertical direction. Thus, in the inclined posture of FIG. 11, the first inner wall surface 116 of the inner wall surface of the battery case 110 is positioned on the lower side in the vertical direction.

  Further, in the inclined posture, the battery case 110 is inclined such that the positive electrode terminal 140 is in the lower side in the vertical direction than the negative electrode terminal 150. FIG. 11 shows an angle θ between the first inner wall surface 116 and the horizontal plane H in the inclined posture of the battery case 110.

  FIG. 12 shows a cross-sectional view taken along the line XX of FIG. FIG. 12 shows the length B of the first side 117 of the first inner wall surface 116 on the positive electrode terminal 140 side. The length B of the first side 117 is the length of the internal space of the battery case 110 in the thickness direction of the battery case 110. 12 shows the thickness C of the electrode body 120, which is the length of the electrode body 120 in the stacking direction. The thickness C of the electrode body 120 is the length of the electrode body 120 in the direction of the first side 117.

  In FIG. 12, the surfaces positioned at both ends in the stacking direction of the electrode body 120 are shown as a first surface 125 and a second surface 126, respectively. Furthermore, among the inner wall surfaces of the battery case 110, the inner wall surfaces facing the first surface 125 and the second surface 126 of the electrode body 120 are shown as a second inner wall surface 118 and a third inner wall surface 119, respectively.

  As shown in FIG. 12, the length B of the first side 117 is longer than the thickness C of the electrode body 120. Therefore, between the first surface 125 of the electrode body 120 and the second inner wall surface 118 of the battery case 110 and between the second surface 126 of the electrode body 120 and the third inner wall surface 119 of the battery case 110. , There are gaps. The gap in the thickness direction between the electrode body 120 and the battery case 110 is larger than the other gaps.

  That is, in the battery 200 of the present embodiment, the internal space of the battery case 110 and the outer shape of the electrode body 120 are both rectangular. Of the gaps between the battery case 110 and the electrode body 120, the size of the gap in the height direction of the battery case 110 is slightly smaller than the size of the gap in the thickness direction. Of the gap between the battery case 110 and the electrode body 120, the size of the gap in the width direction of the battery case 110 is also slightly smaller than the size of the gap in the thickness direction.

  Therefore, in the present embodiment, in the tilt holding step, the electrolytic solution 130 is used in the gap between the first surface 125 of the electrode body 120 and the second inner wall surface 118 of the battery case 110 and the second surface 126 of the electrode body 120 and the battery. The case 110 is assumed to be accumulated in a gap with the third inner wall surface 119 of the case 110. Furthermore, in this embodiment, the volume of the electrolytic solution 130 existing in the gap between the electrode body 120 and the battery case 110 is V.

  Note that the volume V of the electrolytic solution 130 accumulated in the gap between the electrode body 120 and the battery case 110 is smaller than the volume of the electrolytic solution 130 injected into the battery case 110 in the housing step. This is because part of the injected electrolytic solution 130 is impregnated in the electrode body 120 and held in the electrode body 120. However, the volume of the electrolytic solution 130 held in the electrode body 120 is a small amount with respect to the volume of the injected electrolytic solution 130. For this reason, in this embodiment, the volume V of the electrolytic solution 130 accumulated in the gap between the electrode body 120 and the battery case 110 is assumed to be equal to the volume of the electrolytic solution 130 injected in the housing process.

  Here, in the battery 200, the positive terminal 140, the negative terminal 150, and the processing terminal 210 are all provided on the sealing plate 112. As shown in FIG. 11, the processing terminal 210 is provided between the positive terminal 140 and the negative terminal 150 in the width direction of the battery case 110. The positive terminal 140 and the processing terminal 210 are both provided on the first side 117 side of the first inner wall surface 116 when viewed from the negative terminal 150. 11 and 12 show a distance A from the first side 117 to the processing terminal 210 on the first inner wall surface 116. FIG.

  In the tilt holding step, the battery case 110 is tilted so that both the positive electrode terminal 140 and the processing terminal 210 are immersed in the electrolytic solution 130. That is, the angle θ in the inclined posture is an angle at which both the positive electrode terminal 140 and the processing terminal 210 inside the battery case 110 are immersed in the electrolytic solution 130.

More specifically, in the present embodiment, the inclination test of the battery case 110 is such that the angle θ satisfies the following formula (1).
θ ≦ tan ⁻¹ [V / {A ² (BC)}] (1)
V: Volume of electrolyte 130 A: Distance from first side 117 to processing terminal 210 on first inner wall surface 116 B: Length of first side 117 C: Thickness of electrode body 120

  In the tilt holding process, the metal ions in the electrolytic solution 130 can be removed from the electrolytic solution 130 by holding the battery case 110 in the tilted posture. That is, in the electrolyte solution 130 of the battery 200 at the start of the tilt holding process, metal ions related to the metal foreign matter dissolved in the compression heating process and the release cooling process may exist. Further, the positive electrode potential adjusted to the dissolution potential of the metal foreign matter in the potential adjusting step is also high in the tilt holding step.

  For this reason, in the tilt holding process, while the battery case 110 is held in a tilted posture, the metal ions in the electrolytic solution 130 move toward the processing surface 211 of the processing terminal 210 whose potential is lower than the positive electrode potential. Furthermore, the metal ions that have moved toward the processing surface 211 of the processing terminal 210 are deposited as metal on the processing surface 211 of the processing terminal 210. Thereby, in the tilt holding step, metal ions related to the metal foreign matter can be removed from the electrolytic solution 130. Further, the time for holding the battery case 110 in an inclined posture may be determined in advance according to conditions such as the potential difference between the potential of the processing terminal 210 and the positive electrode potential, the size of the mixed metal foreign matter, the amount of the electrolytic solution 130, and the like. .

  Then, by the foreign substance processing step of this embodiment, the battery 200 can be made to suppress metal deposition thereafter. This is because the metal ions generated by the dissolution of the metal foreign matter are removed from the electrolytic solution 130 in the tilt holding step of the foreign matter treatment step.

  In the tilt holding step, it is preferable to tilt the battery case 110 so that the negative electrode terminal 150 is not immersed in the electrolyte solution 130. That is, it is preferable that the angle θ in the inclined posture is an angle at which the inner side of the battery case 110 of the negative electrode terminal 150 is not immersed in the electrolytic solution 130. Here, FIGS. 11 and 12 show a distance D from the first side 117 to the negative electrode terminal 150 in the first inner wall surface 116.

More specifically, in the present embodiment, it is preferable that the inclined posture of the battery case 110 is a posture in which the angle θ satisfies both the above formula (1) and the following formula (2).
θ> tan ⁻¹ [V / {D ² (BC)}] (2)
V: Volume B of electrolytic solution 130: Length of first side 117 C: Thickness of electrode body 120 D: Distance from first side 117 to negative electrode terminal 150 on first inner wall surface 116

  In the tilt holding step, the battery case 110 is tilted so that the negative electrode terminal 150 is not immersed in the electrolytic solution 130, so that metal ions in the electrolytic solution 130 generated by the dissolution of the metal foreign matter are used as the negative electrode. It can prevent that it precipitates. And since the metal precipitation in a negative electrode can be prevented, the fine short circuit which arises by metal precipitation can be prevented. Furthermore, since the metal deposition in the negative electrode can be prevented, the decrease in the exposed surface area of the negative electrode accompanying the metal deposition can be prevented, so that the decrease in battery capacity can also be suppressed.

  Next, Examples 1 and 2 according to the above embodiment will be described together with comparative examples. Example 1 relates to the first aspect described above. Example 2 relates to the second embodiment described above. That is, Example 1 and Example 2 are different in the foreign matter processing step. Further, in the comparative example, the foreign substance processing step is performed by a method different from both of the first and second embodiments.

  And Example 1, 2 and the comparative example were all performed similarly until the accommodation process. In other words, basically the same battery composition and materials are used. However, in the second embodiment, a processing terminal is provided.

  In each of Examples 1 and 2 and the comparative example, SUS particles (SUS303) having a diameter of 100 μm were mixed in the battery in the process before the housing process. The SUS particles are assumed to be metallic foreign matters. Further, since SUS particles are mainly composed of iron, the dissolution potential is about 2.5 V (vs. Li / Li +) or more. The location where SUS particles were mixed was between the positive electrode plate and the separator.

  In Example 1, the foreign matter processing step described in the first embodiment is performed. In Example 2, the foreign matter processing step described in the second embodiment is performed. In the comparative example, a foreign matter processing step different from any of the above embodiments is performed.

  Specifically, in both Examples 1 and 2, in the potential adjustment step, the positive electrode potential was set to 3.5 V (vs. Li / Li +), which is the dissolution potential of SUS particles. In both Examples 1 and 2, in the compression heating process, the compression load was set to 0.1 MPa, and the heating temperature was set to 50 ° C. Furthermore, in both Examples 1 and 2, in the release cooling process, the compression load was set to 0.05 MPa, and the cooling temperature was set to −5 ° C. In both Examples 1 and 2, the compression heating process and the release cooling process were repeated 10 times alternately. Each time of the compression heating process and the release cooling process was 10 minutes. In addition, for Example 2, the battery case was held in an inclined posture for 30 minutes in an environment at 25 ° C. in the inclination holding step.

  Note that the time required for the foreign matter processing step of Example 1 is about 200 minutes. The time required for the foreign matter processing step of Example 2 is about 230 minutes.

  In the comparative example, the potential adjustment step and the leaving step were performed in the foreign matter processing step. That is, in the comparative example, neither the compression heating process nor the release cooling process is performed. Also in the comparative example, the potential adjustment step was performed under the same conditions as in the example. In the leaving step of the comparative example, the battery after the potential adjustment step was left for 600 minutes in a posture not tilted with the sealing plate of the battery case facing upward. The time required for the foreign matter processing step of the comparative example is about 600 minutes. That is, in the comparative example, the foreign matter processing step was performed for a longer time than both of the first and second embodiments.

  And the battery voltage and the capacity maintenance rate were acquired about each battery of Example 1, 2 produced by said implementation method, and a comparative example, and those comparison was performed. The battery voltage and capacity retention rate acquisition method is the same for Examples 1 and 2 and the comparative example.

  FIG. 13 shows changes in battery voltage obtained from the batteries of Examples 1 and 2 and the comparative example. The transition of the battery voltage shown in FIG. 13 is obtained by measuring the open circuit voltage for a certain period of time for each battery charged until the battery voltage reaches 4.1V.

  As shown in FIG. 13, in the battery of the comparative example, the battery voltage decreases with the passage of time. This is considered to be because the mixed SUS particles were not properly dissolved and diffused in the foreign matter processing step of the comparative example. Therefore, in the battery of the comparative example, it is considered that the metal voltage eluted from the SUS particles is deposited on the negative electrode plate as a metal, and a short circuit occurs in the electrode body, thereby reducing the battery voltage.

  On the other hand, in both the batteries of Examples 1 and 2, as shown in FIG. 13, the battery voltage did not decrease with the passage of time. This is considered to be because, in both Examples 1 and 2, the mixed SUS particles were appropriately dissolved and diffused in the foreign matter processing step. Therefore, in the batteries of Examples 1 and 2, it is considered that the micro short circuit inside the electrode body as in the comparative example is suppressed, and the battery voltage does not decrease.

  FIG. 14 shows the transition of the capacity retention rate obtained from the batteries of Examples 1 and 2 and the comparative example. The transition of the capacity maintenance ratio shown in FIG. 14 is obtained by measuring the capacity maintenance ratio while performing a cycle test in which charging and discharging are repeated.

  As shown in FIG. 14, in the battery of the comparative example, the capacity retention rate rapidly decreases with an increase in the number of cycles, which is the number of times charging and discharging are repeated. In other words, in the battery of the comparative example, the capacity maintenance rate is lowered early after the start of the cycle test. Therefore, it can be seen that the battery of the comparative example is easily deteriorated and has low durability.

  In the foreign matter processing step of the comparative example, as described above, it is considered that the SUS particles were not properly dissolved and diffused. For this reason, in the battery of the comparative example, it is considered that the remaining SUS particles remaining inside the battery after the foreign substance treatment step were large and the concentration of metal ions around the remaining SUS particles was also high. Therefore, in the battery of the comparative example, it is considered that a large metal precipitate was formed on the negative electrode plate at an early stage of the cycle test, so that the capacity retention rate was lowered early.

  On the other hand, in both the batteries of Examples 1 and 2, as shown in FIG. That is, it can be seen that the batteries of Examples 1 and 2 are both highly durable batteries that are less likely to deteriorate. In both the foreign substance processing steps of Examples 1 and 2, it is considered that the SUS particles were appropriately dissolved and diffused.

  Furthermore, it can be seen from FIG. 14 that the battery of Example 2 is less susceptible to deterioration and has higher durability than the battery of Example 1. In the first embodiment, the tilt holding process is not performed in the foreign substance processing process. For this reason, in the battery of Example 1, metal ions generated by dissolution of the SUS particles remain in the electrolytic solution in a diffused state. On the other hand, in Example 2, metal ions are removed from the electrolytic solution in the tilt holding process of the foreign substance processing process.

  That is, in the battery of Example 2, the concentration of metal ions in the electrolytic solution is lower than that of the battery of Example 1. Thereby, in the battery of Example 2, it is thought that precipitation of the metal accompanying the repetition of charging / discharging does not arise easily and the durability is higher than the battery of Example 1. Therefore, in Example 2 which concerns on a 2nd form, it is thought that the SUS particle mixed in the inside of a battery case has been processed more appropriately.

  Further, in order to produce a battery having the same durability as that of the battery of Example 1 by a method according to the comparative example, the leaving step in the foreign matter treatment process is further prolonged (that is, longer than 600 minutes). ,It must be made. That is, in the method according to the comparative example, it takes a long time for the foreign matter processing step to properly treat the foreign matter in the foreign matter processing step. On the other hand, in Examples 1 and 2, it was confirmed that the foreign material processing step in which metal foreign materials are appropriately processed can be performed in a short time.

  As described above in detail, the method for manufacturing a lithium ion secondary battery according to the present embodiment includes a housing step and a foreign matter processing step. In the foreign matter processing step, a potential adjustment step for adjusting the positive electrode potential to the dissolution potential of the metallic foreign matter is performed. Furthermore, a compression heating process and a release cooling process are performed on the battery adjusted to the dissolution potential of the metal foreign matter. In the compression heating step, a compression load is applied from the outside of the battery case in the electrode stacking direction, and the battery case is heated. In the release cooling process, the compression load on the battery case is made lower than that in the compression heating process, and the battery temperature is lowered than in the compression heating process. As a result, a method of manufacturing a lithium ion secondary battery that can appropriately process the metal foreign matter mixed in the battery case and can process the metal foreign matter in a short time has been realized.

  Note that this embodiment is merely an example, and does not limit the present invention. Accordingly, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, the present invention is not limited to the lithium ion secondary battery having the wound flat electrode body described in the above embodiment, but is a stacked type in which positive and negative electrode plates are stacked by flat stacking with a separator interposed therebetween. The present invention can also be applied to a lithium ion secondary battery having an electrode body.

  For example, the number of times of the compression heating process and the release cooling process is not limited to ten. The compression heating process and the release cooling process are performed at least once, and the effect is exhibited more than when not performed. Further, for example, the release cooling process does not necessarily have to release the battery case from the pressure. In other words, in the release cooling process, the restraining pressure on the battery case may be reduced as compared with the pressure heating process. Further, for example, the open cooling step does not necessarily have to lower the battery temperature below room temperature. The release cooling process only needs to reduce the battery temperature as compared to the compression heating process.

  In the second embodiment, the arrangement of the positive terminal and the processing terminal may be reversed. That is, the processing terminal may be provided on the first side of the positive inner terminal on the first inner wall surface of the battery case. In this case, the distance A used in the expression (1) may be “a distance from the first side on the first inner wall surface to the processing terminal positive terminal”.

  Further, for example, a battery voltage inspection process may be performed between the housing process and the foreign substance processing process. In the battery voltage inspection step, the open-circuit voltage of the battery is measured, and a battery with a large amount of decrease in battery voltage with respect to elapsed time during the measurement period can be determined as defective. Further, such a battery voltage inspection step may be performed after the foreign matter processing step.

  Further, for example, in the foreign matter processing step, the electrolyte solution may be replaced after the compression heating step and the release cooling step. This is because the metal ions generated by the dissolution of the metal foreign matter can be removed from the battery by removing the electrolytic solution from the battery after the metal foreign matter is dissolved. Such replacement of the electrolytic solution is particularly preferably applied in the first embodiment. This is because, in the first embodiment described above, metal ions generated by dissolution of metal foreign matter remain in the electrolytic solution. On the other hand, in the second embodiment, an inclined holding process is performed in which metal ions generated by dissolution of the metal foreign matter are removed from the electrolytic solution.

100, 200 Battery 110 Battery case 120 Electrode body 130 Electrolyte 140 Positive electrode terminal 150 Negative electrode terminal 160 Positive electrode plate 170 Negative electrode plate 180 Separator

Claims (3)

An electrode body formed by laminating a positive electrode plate and a negative electrode plate with a separator interposed therebetween,
A battery case containing the electrode body together with an electrolytic solution;
A lithium ion secondary battery provided in the battery case, having one end side connected to the electrode body inside the battery case and the other end side exposed to the outside of the battery case. In the manufacturing method of
A housing step of housing the electrode body and the electrolyte in the battery case;
A foreign matter treatment step for treating the metal foreign matter mixed inside the battery case by setting the positive electrode potential to a predetermined dissolution potential of the metal foreign matter,
The foreign matter processing step includes
A first step of applying a compression load in the stacking direction of the electrode body from the outside of the battery case and heating the battery case;
A lithium ion secondary battery comprising: a second step of lowering the compression load on the battery case than that of the first step and lowering a battery temperature than that of the first step. Production method. In the manufacturing method of the lithium ion secondary battery of Claim 1,
The battery case is
The space enclosed by the inner wall is rectangular.
A process in which at least a part of the first inner wall surface, which is one of the inner wall surfaces, is exposed in the battery case together with the positive electrode terminal and the negative electrode terminal and is not electrically connected to the electrode body. A terminal is provided,
The positive terminal and the processing terminal are both provided on the first side of the first inner wall surface when viewed from the negative terminal,
The foreign matter processing step includes
The battery case is implemented after the first step and the second step, and the battery case is positioned in the vertical direction with respect to the negative electrode terminal while the first inner wall surface is set to the lower side in the vertical direction. The angle θ between the first inner wall surface and the horizontal plane in the inclination is expressed by the following equation:
θ ≦ tan ⁻¹ [V / {A ² (BC)}]
V: Volume A of the electrolytic solution A: Distance B from the first side of the first inner wall surface to the one of the positive terminal and the processing terminal that is farther from the first side B: First side length C: a lithium ion secondary battery having a third step of holding for a predetermined time as a posture satisfying the length of the electrode body in the direction of the first side Manufacturing method. In the manufacturing method of the lithium ion secondary battery of Claim 2,
In the third step,
The attitude of the battery case is expressed by the following equation:
θ> tan ⁻¹ [V / {D ² (BC)}]
D: A method of manufacturing a lithium ion secondary battery, characterized in that the posture satisfies a distance from the first side of the first inner wall surface to the negative electrode terminal.

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