Battery cell manufacturing method

Abstract

This suppresses the effects of heat on the power generation elements during the manufacturing of battery cells. [Solution] In the method for manufacturing the battery cell 1, electrode sheets 3 and 4, each having electrodes 32 and 42 located inside a container 10 and current collectors 31 and 41 connected to the electrodes inside the container and protruding outwards from openings 12 and 13 of the container, are stacked in the stacking direction to form a power generation element 2. A resin 51 located between the stacked current collectors is pressurized and heated at the opening of the container from the outside in the stacking direction toward the center, promoting the transfer of heat from the power generation element to the outside of the power generation element, and welding the resin between the current collectors while sealing the opening of the container.

Description

Technical Field

[0001] The technology disclosed herein relates to a method for manufacturing a battery cell.

Background Art

[0002] Patent Document 1 describes a conventional laminated battery. A laminated battery is a battery in which an electrode body is housed in an exterior member. The laminated battery includes a plurality of current collecting terminals drawn out from the electrode body to the outside of the exterior member. The plurality of current collecting terminals overlap with a thermoplastic resin interposed therebetween. At the peripheral edge of the exterior member, the resins are welded to each other and welded to the exterior member, whereby the peripheral edge of the exterior member from which the current collecting terminals are drawn out is closed. In a laminated battery, each of the plurality of current collecting terminals is drawn out to the outside of the exterior member. The plurality of current collecting terminals are not connected to each other inside the exterior member. In a laminated battery, the space inside the exterior member can be used for the expansion of the electrode body. The structure of the laminated battery is advantageous for improving the energy density of the battery.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The above-mentioned laminated battery is manufactured by a heat-sealing process. In the heat-sealing process, the resins overlapping at the peripheral edge of the exterior member are welded to each other when a hot plate, which is an energy supply source, is pressed against them in the overlapping direction.

[0005] In the laminated battery described above, the electrode body expands within the outer casing, as previously mentioned. The electrode body is located near the periphery of the outer casing. During the heat sealing process, when the resin is heated by a hot plate, there is a risk that the temperature of the electrode body near the hot plate may become excessively high. If the temperature of the electrode body becomes too high, the separator of the electrode body may shrink due to heat, which may cause a short circuit in the electrode in the laminated battery after manufacturing.

[0006] The technology disclosed herein suppresses the effects of heat on the power generation element during the manufacturing of battery cells. [Means for solving the problem]

[0007] The technology disclosed herein relates to a method for manufacturing battery cells. In this manufacturing method, An electrode sheet having an electrode located inside a container and a current collector connected to the electrode inside the container and protruding outwards from the opening of the container is stacked in the stacking direction to form a power generation element. The resin located between the stacked current collectors is pressurized and heated at the opening of the container, moving from the outside in the stacking direction toward the center. While the resin is pressurized and heated, the transfer of heat from the power generation element to the outside of the power generation element is promoted, and, The resin is welded between the current collectors, and the opening of the container is sealed.

[0008] In battery cells manufactured using this method, each of the stacked current collectors protrudes out of the container through an opening. The multiple current collectors are connected, for example, to electrodes of the same polarity. The multiple current collectors are not connected to each other inside the container. The connection space between current collectors inside the container can be eliminated. The power generation element, including the electrodes, can be enlarged using the space inside the container. Battery cells with this structure can have a high energy density.

[0009] The opening of the container is sealed with resin. The resin is, for example, a thermoplastic resin. During the manufacturing of the battery cell, at the location of the container opening, the resin between the stacked current collectors is pressurized and heated from the outside in the stacking direction toward the center. For example, a pair of heating plates located on the outside of the container may be used to pressurize and heat the resin by supplying thermal energy to the resin from the outside in the stacking direction toward the center, while sandwiching multiple layers of resin in the stacking direction. The resin is then welded between the current collectors, sealing the opening of the container.

[0010] Here, the power generation element extends close to the opening of the container. While the resin sealing the opening is pressurized and heated, the power generation element may also be heated, potentially leading to an excessive temperature increase.

[0011] In the above manufacturing method, heat transfer from the power generation element to the outside of the power generation element is promoted while the resin is pressurized and heated. The rise in temperature of the power generation element is suppressed. The power generation element is less affected by heat during the manufacturing of the battery cell. The occurrence of defects in the battery cell after manufacturing is suppressed.

[0012] The electrode sheet may further have a separator that contacts the electrode on the side opposite to the current collector and separates the electrodes from each other in the stacking direction between the stacked electrode sheets.

[0013] The separator may shrink due to heat. As mentioned above, the temperature rise of the power generation element is suppressed while the resin is pressurized and heated, thus suppressing the thermal shrinkage of the separator. This can suppress the occurrence of short circuits in the electrodes of the battery cells after manufacturing.

[0014] The stacked resin is sandwiched in the stacking direction by a pair of heating plates located on the outside of the container, thereby pressurizing and heating the resin. During the pressurization and heating of the resin, the heat sink may contact the outer surface of the container at a position corresponding to the electrodes of the power generation element, thereby promoting the transfer of heat from the power generation element to the heat sink.

[0015] When a hot plate is used to pressurize and heat the resin, heat from the hot plate is easily transferred to the power generation element located near the resin.

[0016] In contrast, the heat sink contacts the outer surface of the container at positions corresponding to the electrodes of the power generation element, thereby promoting heat transfer from the power generation element to the heat sink. As a result, the temperature rise of the power generation element is suppressed. Note that the positions corresponding to the electrodes of the power generation element are also the positions corresponding to the separator of the power generation element. Thermal contraction of the separator is suppressed.

[0017] The heat sink may be in contact with the outer surface of the container even before the resin is pressurized and heated.

[0018] If the heat sink is in contact with the outer surface of the container beforehand, heat transfer from the power generation element to the heat sink will begin immediately after the resin is pressurized and heated. This effectively suppresses the temperature rise of the power generation element.

[0019] The heat sink may be cooled by a cooling device.

[0020] Cooling the heat sink further promotes heat transfer from the power generation element to the heat sink, thereby further suppressing the temperature rise of the power generation element.

[0021] Before pressurizing and heating the resin, preheating of the resin through the current collector may be initiated.

[0022] When a pair of heating plates located on the outside of a container are used to sandwich multiple resins in the stacking direction, and thermal energy is supplied to the resins from the outside towards the center in the stacking direction, the thermal energy is transferred sequentially from the resins on the outside towards the center. Due to attenuation, the thermal energy supplied to the resins located towards the center in the stacking direction tends to be lower than the thermal energy supplied to the resins located on the outside in the stacking direction.

[0023] In the above manufacturing method, before starting the pressurization and heating of the resin, the resin is preheated through the current collector. Heat energy is efficiently supplied to the resin located on the central side in the stacking direction through the current collector located on the central side in the stacking direction.

[0024] The preheating of the resin through the current collector, combined with the pressurization and heating from the outside in the stacking direction, sufficiently supplies heat energy to both the resin located on the outside in the stacking direction and the resin located on the central side in the stacking direction. As a result, all the resins are welded throughout the entire stacking direction during the manufacture of the battery cell. Variations in the sealing strength of the opening of the container depending on the site are suppressed.

[0025] While the preheating through the current collector improves the sealing quality of the opening of the container, if the current collector is heated, heat is also transmitted to the power generation element through the current collector. The temperature of the electrode or separator is likely to increase. In contrast, in the above manufacturing method, by promoting the transfer of heat from the power generation element to the outside of the power generation element, the temperature rise of the power generation element can be effectively suppressed.

[0026] The preheating through the current collector may also be continued after the start of the pressurization and heating of the resin.

[0027] If the preheating through the current collector is terminated during the pressurization and heating of the resin, the temperature of the resin may drop due to heat dissipation through the current collector. By continuing the preheating through the current collector after the start of the pressurization and heating of the resin, heat dissipation through the current collector is suppressed. All the resins are welded and the opening of the container is stably sealed.

[0028] After the pressurization and heating of the resin are completed, it is also possible to continue promoting the transfer of heat from the power generation element to the outside of the power generation element.

[0029] Even after the pressurization and heating of the resin are completed, the temperature of the power generation element is relatively high. If the promotion of the transfer of heat from the power generation element to the outside of the power generation element is continued, the temperature of the power generation element will rapidly decrease. The influence of heat on the power generation element during the manufacture of the battery cell is suppressed. [Effects of the Invention]

[0030] The aforementioned method for manufacturing battery cells can suppress the influence of heat on the power generation element during the manufacturing of the battery cell. [Brief explanation of the drawing]

[0031] [Figure 1] Figure 1 is a cross-sectional view of a battery cell. [Figure 2] Figure 2 shows part of the battery cell manufacturing procedure. [Figure 3] Figure 3 shows part of the battery cell manufacturing procedure. [Figure 4] Figure 4 shows part of the battery cell manufacturing procedure. [Figure 5] Figure 5 shows part of the battery cell manufacturing procedure. [Figure 6] Figure 6 shows part of the battery cell manufacturing procedure. [Modes for carrying out the invention]

[0032] The following describes an embodiment of the battery cell manufacturing procedure with reference to the drawings. The battery cell manufacturing procedure described here is illustrative.

[0033] (Battery cell structure) Figure 1 schematically shows the overall structure of battery cell 1. Battery cell 1 is a secondary battery. Battery cell 1 is, for example, a lithium-ion battery.

[0034] The battery cell 1 is a so-called pouch-type battery. The battery cell 1 comprises a power generation element 2 and a container 10. The container 10 is sealed with the power generation element 2 and electrolyte contained within it. The container 10 is made by folding one sheet of laminate material 11 or by overlapping two sheets of laminate material 11 to form a bag. The laminate material 11 has a three-layer structure, for example, a metal layer sandwiched between resin layers on both sides. The metal layer is, for example, aluminum or stainless steel. The resin layer is, for example, polypropylene (PP) or polyethylene (PE).

[0035] The power generation element 2 has a first electrode sheet 3. The first electrode sheet 3 is, for example, a negative electrode sheet. The power generation element 2 also has a second electrode sheet 4. The second electrode sheet 4 is, for example, a positive electrode sheet. The first electrode sheet 3 and the second electrode sheet 4 overlap alternately. The number of first electrode sheets 3 and second electrode sheets 4 in the power generation element 2 is arbitrary. The power generation element 2 is an electrode stack. In the following, the direction in which the first electrode sheet 3 and the second electrode sheet 4 are stacked may be referred to as the stacking direction. The stacking direction is the vertical direction on the paper in Figure 1 and Figures 2 to 6 described later.

[0036] The first electrode sheet 3 has a current collector 31. The current collector 31 is a thin plate or foil extending in a direction perpendicular to the lamination direction. The end of the current collector 31, that is, the left end in Figure 1, protrudes out of the container 10 through the first opening 12 of the container 10.

[0037] An active material is applied to the first and second surfaces of the current collector 31 located inside the container 10. The first surface is the upper surface of the current collector 31 in Figure 1, and the second surface is the lower surface of the current collector 31 in Figure 1. The active material forms the first electrode 32. The current collector 31 is connected to the first electrode 32 inside the container 10.

[0038] The first electrode sheet 3 has a separator 33. The separator 33 separates the first electrode 32 of the first electrode sheet 3 from the second electrode 42 of the second electrode sheet 4, which will be described later. The separator 33 is, for example, a porous material that allows ionic substances to pass through.

[0039] The separator 33 covers the surface of each of the two first electrodes 32 on the first electrode sheet 3. The separator 33 may be formed by attaching a film to the first electrodes 32. Alternatively, the separator 33 may be formed by drying a slurry applied to the first electrodes 32. The area of ​​the separator 33 may be the same as the area of ​​the first electrode sheet 3, or it may be larger than the area of ​​the first electrode sheet 3.

[0040] The second electrode sheet 4 has a current collector 41. The current collector 41 is a thin plate or foil extending in a direction perpendicular to the lamination direction. The end of the current collector 41, that is, the right end in Figure 1, protrudes out of the container 10 through the second opening 13 of the container 10. The second opening 13 is the opposite opening to the first opening 12 in the direction perpendicular to the lamination direction. Note that the protruding direction of the current collector 41 is not limited to the opposite direction of the protruding direction of the current collector 31.

[0041] An active material is applied to the first and second surfaces of the current collector 41 located inside the container 10. The active material forms the second electrode 42. The current collector 41 is connected to the second electrode 42 inside the container 10.

[0042] As mentioned above, the first electrode sheet 3 and the second electrode sheet 4 are stacked alternately. The first electrode 32 and the second electrode 42 are stacked in the stacking direction inside the container 10 via the separator 33.

[0043] The first opening 12 of the container 10 is sealed with resin 5. Resin 5 is a sealing material. Resin 5 is located between the laminate material 11 and the current collector 31, and between the current collectors 31. Similarly, the second opening 13 is sealed with resin 5. Resin 5 is located between the laminate material 11 and the current collector 41, and between the current collectors 41.

[0044] Multiple current collectors 31 are not connected inside the container 10, but protrude individually outside the container 10. Similarly, multiple current collectors 41 are not connected inside the container 10, but protrude individually outside the container 10. Since the connection space for the current collectors 31 and 41 inside the container 10 can be eliminated, the area of ​​the first electrode 32 and the second electrode 42 can be increased by the amount of space saved. In Figure 1, the edge of the first electrode sheet 3 is located near the openings 12 and 13 of the container 10. The battery cell 1 can have a high energy density.

[0045] (Method of manufacturing battery cells) Next, the manufacturing method of the battery cell 1 will be described with reference to Figures 2, 3, 4, 5, and 6. The manufacturing method of the battery cell 1 proceeds in the order shown in Figures 2, 3, 4, 5, and 6. Here, the manufacturing method of the battery cell 1 will be explained using the welding of resin at the first opening 12 as an example, but the welding of resin at the second opening 13 is similar.

[0046] First, the first electrode sheet 3 and the second electrode sheet 4 are prepared. As described above, the first electrode sheet 3 has a current collector 31, a first electrode 32, and a separator 33. The first electrode sheet 3 also has a resin 51 (see Figure 2). The resin 51 is located in the current collector 31 between the end of the current collector 31 and the first electrode 32. The resin 51 is pre-welded to the first and second surfaces of the current collector 31, respectively.

[0047] The second electrode sheet 4 comprises a current collector 41, a second electrode 42, and resin. The resin of the second electrode sheet 4, like the resin 51 of the first electrode sheet 3, is located between the end of the current collector 41 and the second electrode 42. The resin is pre-welded to the first and second surfaces of the current collector 41.

[0048] Next, as shown in Figure 2, the first electrode sheet 3 and the second electrode sheet 4 are stacked alternately. As shown in Figure 3, the first electrode 32 and the second electrode 42 overlap via a separator 33. The resin 51 is located between the current collectors 31 of the first electrode sheet 3. The resin 51 is aligned in the stacking direction. In addition, resin is also located between the current collectors 41 of the second electrode sheet 4.

[0049] Resin 51 is a thermoplastic resin. Resin 51 is selected from unoriented polypropylene (CPP), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), biaxially oriented polypropylene (OPP), polyethylene terephthalate (PET), or biaxially oriented nylon (ONY).

[0050] After the first electrode sheet 3 and the second electrode sheet 4 are laminated to form the power generation element 2, the laminate material 11 is placed over the power generation element 2. As shown in Figure 3, the position of the edge of the laminate material 11 (the left edge in Figure 3) corresponds to the position of the resin 51. Also, the laminate material 11 is located outside the outermost current collector 31 in the lamination direction. In other words, the laminate material 11 is located above the uppermost current collector 31 and below the lowermost current collector 31 in the vertical direction in Figure 3.

[0051] Next, the cooling of the power generation element 2 is started. The cooling of the power generation element 2 is performed using heat sinks 63, 63. The heat sinks 63, 63 are in contact with the outer surface of the laminate material 11. The heat sinks 63, 63 are positioned at locations corresponding to the first electrode 32 and separator 33 of the power generation element 2. The heat sinks 63, 63 are indirectly in contact with the power generation element 2 through the laminate material 11.

[0052] The length of the heat sinks 63, 63 in the direction perpendicular to the stacking direction may correspond to the length of the first electrode 32 and the separator 33. The length of the heat sinks 63, 63 may be shorter than the length of the first electrode 32 and the separator 33.

[0053] The heat sinks 63, 63 are adjacent to at least the resin 51. This is to promote heat transfer from the power generation element 2 adjacent to the resin 51 to the heat sinks 63 when the resin 51 is heated by the first heat plate 61 or the second heat plate 62, which will be described later.

[0054] The heat sink 63 is connected to the chiller 64. A heat transfer medium circulates between the heat sink 63 and the chiller 64 (see arrow in Figure 3). The chiller 64 cools the heat sink 63 via the heat transfer medium. The chiller 64 is an example of a cooling device for cooling the heat sink 63. Note that the cooling device is not limited to the chiller 64.

[0055] After the cooling of the power generation element 2 begins, preheating of the resin 51 is started, as shown in Figure 4. The preheating of the resin 51 is performed using a pair of first heat plates 61, 61. The pair of first heat plates 61, 61 sandwich the multiple current collectors 31 in the stacking direction at the ends of the current collectors 31. The multiple current collectors 31 overlap in the stacking direction. The high-temperature first heat plates 61, 61 heat the multiple current collectors 31 while they are stacked in the stacking direction. As shown by the white arrows in Figure 4, thermal energy is supplied from the pair of first heat plates 61, 61 to the resin 51 through the current collectors 31. In Figure 4, an arrow is drawn only for the current collector 31 in the center of the stacking direction, but thermal energy is supplied to each of the resins 51 in contact with each current collector 31 through each current collector 31. Each resin 51 is heated up.

[0056] As the current collector 31 heats up, heat is transferred to the first electrode 32, the second electrode 42, and the separator 33 of the power generation element 2. If the temperature of the separator 33 becomes too high, there is a risk that the separator 33 will shrink due to the heat.

[0057] In contrast, the heat sink 63 promotes heat transfer from the power generation element 2 to the heat sink 63, as shown by the white arrows in Figure 4. This suppresses the temperature rise of the separator 33.

[0058] After preheating of the resin 51 begins, as shown in Figure 5, hot plate welding is initiated to the resin 51 aligned in the lamination direction. Hot plate welding is performed using a pair of second hot plates 62, 62. The pair of second hot plates 62, 62 are located on the outside of the laminate material 11 and pressurize the resin 51 aligned in the lamination direction from the outside toward the center (see gray arrows in Figure 4) and heat the resin 51 aligned in the lamination direction. Preheating by the first hot plates 61, 61 continues even after hot plate welding by the second hot plates 62, 62 has begun.

[0059] Thermal energy from the high-temperature second heating plates 62, 62 is transmitted through the laminate material 11, resin 51, and current collector 31 from the outside in the lamination direction towards the center. The resin 51 melts upon receiving the thermal energy.

[0060] Here, as shown by the white arrows in Figure 5, the thermal energy supplied from the second heat plates 62, 62 to the resin 51 located towards the center in the lamination direction tends to be lower due to attenuation than the thermal energy supplied to the resin 51 located towards the outside in the lamination direction. This may result in insufficient welding of the resin 51 located towards the center in the lamination direction.

[0061] In contrast, the resin 51 located towards the center in the stacking direction is preheated through the current collector 31. The resin 51 located towards the center in the stacking direction is heated through the current collector 31, and thermal energy is also supplied to it in the stacking direction from the second heat plate 62. Sufficient thermal energy is supplied to the resin 51 located towards the center in the stacking direction.

[0062] In this way, sufficient thermal energy is supplied to both the resin 51 located on the outside in the lamination direction and the resin 51 located on the central side in the lamination direction. As shown in Figure 6, at the opening of the container 10 (here, the first opening 12), the space between the laminate material 11 and the current collector 31, and the space between the current collectors 31 themselves, is sealed by the welded resin 5.

[0063] Here, even while the resin 51 is being hot-welded using the second hot plates 62, 62, the heat sink 63 promotes the transfer of heat from the power generation element 2 to the heat sink 63. Because the power generation element 2 has expanded to the vicinity of the resin 51, heat from the second hot plates 62, 62 is easily transferred to the separator 33 of the power generation element 2. The heat sink 63 also suppresses the temperature rise of the separator 33 during the hot-welding process. Thermal contraction of the separator 33 is suppressed.

[0064] As shown in Figure 6, once the welding of the resin 51 is complete, the pressurizing and heating by the second heating plates 62, 62 are terminated, and the heating by the first heating plates 61, 61 is terminated. Note that if the first heating plates 61, 61 move away from the current collectors 31, the current collectors 31 may move away from each other in the stacking direction.

[0065] After heating by the first heating plates 61, 61 and pressurization and heating by the second heating plates 62, 62 are completed, the heat sink 63 remains in contact with the outer surface of the laminate material 11. Heat transfer from the power generation element 2 to the heat sink 63 continues. The temperature of the separator 33 decreases rapidly. The separator 33 is prevented from maintaining a high temperature. Thermal contraction of the separator 33 is suppressed.

[0066] The heat sink 63 separates from the outer surface of the laminate material 11 after a predetermined time has elapsed, for example, after heating by the first heat plates 61, 61 and pressurization and heating by the second heat plates 62, 62 have been completed.

[0067] As described above, during the heat plate welding using the second heat plates 62, 62, the transfer of heat from the power generation element 2 to the heat sink 63 is promoted using the heat sink 63. Since the temperature rise of the separator 33 of the power generation element 2 is suppressed, the thermal contraction of the separator 33 is suppressed. Short circuits between the electrodes 32 and 42 are suppressed in the battery cell 1 after manufacturing. A battery cell 1 in which the multiple current collectors 31 are not connected inside the container 10, and the area of ​​the first electrode 32 and the second electrode 42 is enlarged accordingly, can be stably manufactured by the above manufacturing method.

[0068] Furthermore, in the manufacturing method described above, the resin 51 is preheated using the first heat plates 61, 61 before starting the heat plate welding using the second heat plates 62, 62. Sufficient thermal energy is supplied to both the resin 51 located towards the center in the lamination direction and the resin 51 located towards the outside in the lamination direction.

[0069] Furthermore, preheating the resin 51 through the current collector 31 prior to hot plate welding can shorten the time from when pressurization and heating from the outside in the lamination direction begin until sufficient thermal energy is supplied to the resin 51 on the central side in the lamination direction. This can suppress the supply of excessive thermal energy to the resin 51 on the outside in the lamination direction.

[0070] As a result, variations in the sealing strength of the openings 12 and 13 of the container 10 are suppressed. Since all the resin 51 can be stably welded, the sealing quality of the openings 12 and 13 of the container 10 is improved.

[0071] Furthermore, since preheating through the current collector 31 by the first heat plates 61, 61 continues even after the heat plate welding using the second heat plates 62, 62 has started, heat dissipation through the current collector 31 is suppressed during heat plate welding with the second heat plates 62, 62. Because the temperature drop of the resin 51 due to heat dissipation is suppressed, the resin 51 can be sufficiently welded.

[0072] Furthermore, preheating through the current collector 31 by the first heat plates 61, 61 ends when the heat plate welding using the second heat plates 62, 62 is completed. If preheating through the current collector 31 continues after the completion of heat plate welding, there is a risk of excessive thermal energy being supplied to the resin 51. By ending preheating through the current collector 31 when the heat plate welding is completed, the supply of excessive thermal energy to the resin 51 is suppressed.

[0073] The preheating by the first heating plates 61, 61 through the current collector 31 may be completed before the heating plate welding using the second heating plates 62, 62 is completed.

[0074] Preheating the resin 51 through the current collector 31 is advantageous for improving the sealing quality of the openings 12 and 13 of the container 10. On the other hand, since heat is transferred to the power generation element 2 through the current collector 31, it is disadvantageous for the temperature rise of the separator 33. Promoting heat transfer from the power generation element 2 to the heat sink 63 using the heat sink 63 suppresses the temperature rise of the separator 33 even when preheating the resin 51 through the current collector 31.

[0075] Cooling using the heat sink 63 begins even before preheating of the resin 51 through the current collector 31 starts. While the resin 51 is preheating, the temperature rise of the power generation element 2 is suppressed, and once the heat sink 63 starts welding, it can quickly cool the power generation element 2. The temperature rise of the power generation element 2 is effectively suppressed.

[0076] Furthermore, since the heat sink 63 is cooled using the chiller 64, heat transfer from the power generation element 2 to the heat sink 63 is further promoted. The temperature rise of the power generation element 2 is suppressed more effectively.

[0077] (modified version) The temperatures of the first heating plate 61 and the second heating plate 62 may be the same or different. By individually setting the temperature and heating period of the first heating plate 61 and the temperature and heating period of the second heating plate 62, each of the multiple resins 51 can be properly welded. Individually controlling the preheating by the first heating plate 61 and the heat plate welding by the second heating plate 62 improves the sealing quality of the openings 12 and 13 of the container 10.

[0078] Furthermore, in the manufacturing method of the battery cell 1 described above, the first heating plates 61, 61 heat the multiple current collectors 31 stacked in the stacking direction, but the first heating plates 61, 61 may selectively heat the current collectors 31 located towards the center in the stacking direction.

[0079] Furthermore, in the manufacturing method of the battery cell 1 described above, preheating of the resin 51 using the first heating plates 61, 61 can be omitted.

[0080] Alternatively, instead of hot plate welding using the second hot plate 62, the resin 51 may be welded by supplying energy to the resin 51 from the outside in the lamination direction toward the center, for example, by vibration welding, ultrasonic welding, or high-frequency welding. In various welding methods, even if there is attenuation of energy for welding, the above manufacturing method makes it possible to sufficiently weld the resin located toward the center in the lamination direction by combining it with preheating of the resin through the current collector.

[0081] The cooling device for the heat sink 63 may be omitted. The heat sink may have, for example, heat fins. A heat sink with heat fins may be forcibly cooled, for example, using a fan, or it may be cooled naturally.

[0082] Furthermore, the technology disclosed herein does not preclude the omission of a heat sink 63 that contacts the outer surface of the laminate material 11 in a structure that promotes heat transfer from the power generation element 2 to the outside of the power generation element 2. [Explanation of symbols]

[0083] 1 battery cell 10 containers 12. First opening 13. Second opening 3. First electrode sheet 31 Current collector 32 1st electrode 33 Separator 4. Second electrode sheet 41 Current collector 42 2nd electrode 5 resin 51 Resin 61 1st hot plate 62 2nd hot plate 63 Heat sink 64. Chiller (cooling device)

Claims

1. An electrode sheet having an electrode located inside a container and a current collector connected to the electrode inside the container and protruding outwards from the opening of the container is stacked in the stacking direction to form a power generation element. The resin located between the stacked current collectors is pressurized and heated at the opening of the container, moving from the outside in the stacking direction toward the center. While the resin is pressurized and heated, the transfer of heat from the power generation element to the outside of the power generation element is promoted, and, The resin is welded between the current collectors and the current collectors, and the opening of the container is sealed. A method for manufacturing battery cells.

2. In the method for manufacturing a battery cell according to claim 1, The electrode sheet contacts the electrode on the side opposite to the current collector and further includes a separator between the stacked electrode sheets that separates the electrodes in the stacking direction. A method for manufacturing battery cells.

3. In the method for manufacturing a battery cell according to claim 1, The stacked resin is sandwiched in the stacking direction by a pair of heating plates located on the outside of the container, thereby pressurizing and heating the resin. During the pressurization and heating of the resin, the heat sink contacts the outer surface of the container at a position corresponding to the electrodes of the power generation element, thereby promoting heat transfer from the power generation element to the heat sink. A method for manufacturing battery cells.

4. In the method for manufacturing a battery cell according to claim 3, The heat sink contacts the outer surface of the container even before the resin is pressurized and heated. A method for manufacturing battery cells.

5. In the method for manufacturing a battery cell according to claim 3 or 4, The heat sink is cooled by a cooling device. A method for manufacturing battery cells.

6. In the method for manufacturing a battery cell according to claim 1, Before pressurizing and heating of the resin is initiated, preheating of the resin through the current collector is started. A method for manufacturing battery cells.

7. In the method for manufacturing a battery cell according to claim 6, The preheating through the current collector continues even after the pressurization and heating of the resin begins. A method for manufacturing battery cells.

8. In the method for manufacturing a battery cell according to claim 1, After the pressurization and heating of the resin are completed, the transfer of heat from the power generation element to the outside of the power generation element is continued. A method for manufacturing battery cells.

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