JP7171643B2 - Secondary battery and secondary battery manufacturing method - Google Patents

Description

The present invention relates to a secondary battery and a secondary battery manufacturing method.

In a secondary battery, a power generating body is formed by a structure in which a separator is sandwiched between a positive electrode sheet and a negative electrode sheet. In addition, as a method for housing a secondary battery, there is a laminated structure in which a plurality of positive electrode plates, a plurality of negative electrode plates, and a plurality of separators are laminated in such a manner that the separator is sandwiched between the positive electrode sheet and the negative electrode sheet.

In Patent Document 1, a positive electrode plate, a negative electrode plate, and a separator sandwiched between them are provided, and the separator comprises a porous resin layer and an adhesive layer that is intermittently formed and directly faces the positive electrode plate or the negative electrode plate. is described. In the laminated electrode body described in Patent Document 1, the adhesive layer is arranged so as to leave an adhesive non-existing region of a wavy line pattern continuous from the outer edge of the separator in plan view of the separator.

JP 2019-053862 A

In the laminated electrode body described in Patent Document 1, the purpose is to efficiently impregnate the entire separator with the electrolytic solution through the adhesive-free region. The electrolyte may not be impregnated until Therefore, there is a demand for a structure and a manufacturing method that allow the electrolytic solution to impregnate the entire laminated electrode assembly (laminated body), that is, to allow the electrolytic solution to be impregnated without impregnation unevenness.

The present invention has been made in order to solve such problems. Its purpose is to provide a method.

A secondary battery according to an aspect of the present invention includes a laminate and a case that houses the laminate, and the laminate includes a positive electrode sheet, a negative electrode sheet, and a space between the positive electrode sheet and the negative electrode sheet. and an adhesive layer in which the positive electrode sheet, the separator, and the negative electrode sheet are bonded together, and at least between the separator and the negative electrode sheet or between the separator and the positive electrode sheet The adhesive layer between has a central space arranged in the central part of the laminate as a space to be impregnated with the electrolytic solution, and a plurality of radial flow paths communicating from the central space toward the end. , is a thing.

The secondary battery according to this aspect can be efficiently impregnated with the electrolytic solution by the adhesive layer having the plurality of radial channels and the central space. Thereby, in the secondary battery, it becomes possible to uniformly impregnate the electrolyte solution into the laminate.

Further, the plurality of radial flow paths may be arranged such that the radiation angle of each radial flow path on a plane perpendicular to the stacking direction of the laminate is substantially constant. Alternatively, the plurality of radial channels may be arranged such that the cross-sectional area of each radial channel on the side of the end portion is substantially constant. In any of the configurations, when the laminate has a structure in which the electrolytic solution penetrates substantially uniformly from each side of the case, the electrolytic solution can be evenly impregnated into the laminate.

Alternatively, in the plurality of radial flow paths, the radial angle of the radial flow paths toward a first end, which is one of the ends, on a plane perpendicular to the stacking direction of the laminate is the first It can also be arranged so as to be larger than the radial angle of the radial flow path toward the end other than the end. Alternatively, the plurality of radial flow paths may have a cross-sectional area on the first end side of the radial flow paths toward a first end, which is one of the ends, at an end other than the first end. It can also be arranged so as to be wider than the cross-sectional area of the end portion side of the radial flow path toward the . In any of the configurations, when the laminate has a structure in which a larger amount of electrolytic solution enters from the first end than from the other ends in the case, the electrolytic solution is evenly impregnated into the laminate. be able to.

Further, in the adhesive layer at least between the separator and the negative electrode sheet or between the separator and the positive electrode sheet, adjacent radial channels are separated by walls made of an adhesive. As a result, the radial flow paths can be easily and reliably formed, and the electrolytic solution can be evenly impregnated into the laminate.

Alternatively, in the adhesive layer at least between the separator and the negative electrode sheet or between the separator and the positive electrode sheet, adjacent radial channels are partitioned by walls made of a high-density adhesive, and each radial channel may be a channel having a lower density of adhesive than the wall portion. Thereby, the radial flow paths can be easily formed, and the laminate can be impregnated with the electrolytic solution more evenly.

A secondary battery manufacturing method according to another aspect of the present invention includes a laminate having a positive electrode sheet, a negative electrode sheet, and a separator sandwiched between the positive electrode sheet and the negative electrode sheet; A secondary battery manufacturing method for manufacturing a secondary battery comprising a case, wherein an adhesive layer is disposed between each of the positive electrode sheet, the separator, and the negative electrode sheet, and the positive electrode sheet and the separator and a laminate producing step of laminating the negative electrode sheets and applying pressure from both sides to produce the laminate; housing the laminate produced by the laminate producing step in the case; an impregnation step of impregnating with a liquid, wherein the space to be impregnated with the electrolytic solution is a central space disposed in the central portion of the laminate and a plurality of radial flow paths communicating from the central space toward the end portion. and an adhesive layer forming step of forming the adhesive layer at least between the separator and the negative electrode sheet or between the separator and the positive electrode sheet so as to have

In the secondary battery manufacturing method according to this aspect, the adhesive layer having the plurality of radial flow paths and the central space enables efficient impregnation of the electrolytic solution. This makes it possible to evenly impregnate the laminate with the electrolytic solution when manufacturing the secondary battery.

In addition, in the adhesive layer forming step, the adhesive layer disposed at least between the separator and the negative electrode sheet or between the separator and the positive electrode sheet is formed between adjacent radial channel walls of the plurality of radial channels. and applying an adhesive to the area. As a result, the radial flow paths can be easily and reliably formed, and the electrolytic solution can be evenly impregnated into the laminate.

Alternatively, the adhesive layer forming step includes a step of applying an adhesive to the entire area where the adhesive layer is to be formed, and the adhesive layer disposed at least between the separator and the negative electrode sheet or between the separator and the positive electrode sheet. in the step of forming the plurality of radial channels, the step of pressurizing with a pressurizing member having a convex portion in a region serving as a wall of the adjacent radial channels in the plurality of radial channels, and the gap between the adjacent radial channels is high Between at least the separator and the negative electrode sheet, or between the separator and the negative electrode sheet, partitioned by walls made of an adhesive having a high density such that each radial channel is a channel in which an adhesive having a lower density than the portion of the wall is disposed. It is also possible to form the adhesive layer arranged between the positive electrode sheets. Thereby, the radial flow paths can be easily formed, and the laminate can be impregnated with the electrolytic solution more evenly.

ADVANTAGE OF THE INVENTION By this invention, the secondary battery and its manufacturing method which can be uniformly impregnated with electrolyte solution in the laminated body which laminated|stacked the positive electrode sheet, the separator, and the negative electrode sheet can be provided.

1 is a diagram showing an example of the appearance of a non-aqueous secondary battery according to Embodiment 1. FIG. 3 is a schematic diagram showing an example of a laminate housed in the case of the non-aqueous secondary battery according to Embodiment 1. FIG. FIG. 3 is a diagram showing an example of a laminate housed in the non-aqueous secondary battery according to Embodiment 1 and how the laminate is impregnated with a non-aqueous electrolyte; FIG. 4 is a diagram showing how a part of the laminate in FIG. 3 is impregnated with a non-aqueous electrolyte; FIG. 5 is a schematic diagram showing a laminate housed in a case of a non-aqueous secondary battery according to a comparative example and how the laminate is impregnated with a non-aqueous electrolyte; FIG. 8 is a schematic diagram showing an example of a non-aqueous secondary battery according to Embodiment 2 and a state of impregnation of a non-aqueous electrolyte in a laminate housed therein. FIG. 10 is a perspective view showing another example of the non-aqueous secondary battery according to Embodiment 2 and a state of impregnation of the non-aqueous electrolyte in the laminate housed therein. FIG. 10 is a flowchart for explaining an example of a method for manufacturing a non-aqueous secondary battery according to Embodiment 3; FIG. 9 is a top view showing an example of a manufacturing apparatus used in the manufacturing method of FIG. 8;

Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. Also, for clarity of explanation, the following description and drawings are simplified as appropriate. Also, in the embodiments, the same or equivalent elements may be denoted by the same reference numerals, and overlapping descriptions will be omitted as appropriate.

(Embodiment 1)
Embodiment 1 will be described with reference to FIGS. 1 to 5, taking a non-aqueous secondary battery such as a lithium ion secondary battery as an example of a secondary battery. FIG. 1 is a diagram showing an example of the appearance of a non-aqueous secondary battery according to Embodiment 1. FIG.

As shown in FIG. 1 , the non-aqueous secondary battery 1 according to this embodiment can include a case 10 , a lid 11 , a negative electrode pole 12 and a positive electrode pole 13 . An assembled battery can be formed by combining a plurality of the non-aqueous secondary batteries 1 illustrated in FIG. 1, and the non-aqueous secondary battery 1 can be one cell of the assembled battery.

The case 10 accommodates a power generator that stores the electrical energy of the non-aqueous secondary battery 1 . The lid 11 is a lid for sealing the power generator to the case 10 . Case 10 and lid 11 can be made of, for example, aluminum or its alloy. The negative pole 12 and the positive pole 13 are electrodes that are electrically connected to the power generator in the case 10 and input/output current to/from the power generator. Also, the negative pole 12 and the positive pole 13 may be provided to protrude from the case 10 as shown in FIG.

Although not shown in FIG. 1, in the non-aqueous secondary battery 1, the lid 11 has holes for taking out the negative pole pole 12 and the positive pole pole 13 attached to the power generating body stored in the case from the case. be provided. The negative electrode pole 12 and the positive electrode pole 13 are connected to current collectors provided in the case through extraction holes provided in the lid 11 .

The non-aqueous secondary battery 1 according to the present embodiment has a main feature in the structure of the laminate (laminated electrode assembly) that constitutes the power generating body. See FIGS. 2 to 4 for examples of the structure of the laminate. I will explain while FIG. 2 is a schematic diagram showing an example of a laminate housed in the case 10 of the non-aqueous secondary battery 1. As shown in FIG. FIG. 3 is a diagram showing an example of a laminate housed in the non-aqueous secondary battery 1 and how the laminate is impregnated with a non-aqueous electrolyte. It is a figure which shows the state (state of flow velocity change) of impregnation of aqueous electrolyte solution.

As shown in FIG. 2, the laminate 20 accommodated in the case 10 includes a positive electrode sheet 21, a negative electrode sheet 23, a separator 22 sandwiched between the positive electrode sheet 21 and the negative electrode sheet 23, and an adhesive layer (not shown). and have

The positive electrode sheet 21 and the negative electrode sheet 23 have active material coated regions that form respective electrodes. For example, the positive electrode sheet 21 is coated with LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ or the like as an active material. Further, the negative electrode sheet 23 is coated with an active material such as graphite (C), titanate (Li ₄ Ti ₅ O ₁₂ ), or the like.

The number of positive electrode sheets 21 and the number of negative electrode sheets 23 are not limited. The stacking direction of the laminate 20 can be the direction shown in FIG. In order to function as a power generator, the positive electrode sheet 21 and the negative electrode sheet 23 can be alternately laminated in the laminate 20 , and the separator 22 is sandwiched between the positive electrode sheet 21 and the negative electrode sheet 23 . Also, the separator 22 may be laminated on the electrode plate (the positive electrode sheet 21 or the negative electrode sheet 23 ) on one end or both ends of the laminate 20 .

As shown in FIG. 2, the positive electrode sheet 21 includes an active material-coated region 21a that constitutes an electrode, and a tab portion 21b that is an active material-uncoated region that protrudes from the active material-coated region 21a. , can have The negative electrode sheet 23 can similarly have an active material coated region 23a and a tab portion 23b.

The adhesive layer described above is a layer that bonds between the positive electrode sheet 21, the separator 22, and the negative electrode sheet 23, and can have an adhesive such as a thermoplastic resin for bonding. This adhesive layer is exemplified by the adhesive layer 24 in FIG. 3, and the details thereof will be described later.

The thickness of the adhesive layer 24 between one electrode sheet and one separator 22 is preferably uniform on one side, and the thickness is common to all of the plurality of adhesive layers 24 included in the laminate 20. is preferred. In addition, in the present embodiment, it is assumed that the laminate 20 is manufactured by laminating the positive electrode sheet 21 or the negative electrode sheet 23 to the separator 22 pre-applied with an adhesive for forming an adhesive layer. However, the adhesive may be applied to the positive electrode sheet 21 and the negative electrode sheet 23 in advance.

In order to function as a power generating body, such a laminate 20 is housed in the case 10, and a liquid injection port (not shown) (for example, a hole formed in the lid 11 before the negative electrode pole 12 and the positive electrode pole 13 are attached). etc.) to impregnate the laminate 20 with a non-aqueous electrolyte such as an organic solvent. In addition, the laminate 20 is impregnated with a non-aqueous electrolyte from the end surface of the laminate 20 through between the electrode plate and the separator 22 (that is, through the adhesive layer), so that the laminate 20 can be used as a power generation body. can function.

The non-aqueous electrolyte is a composition containing a supporting electrolyte in a non-aqueous solvent. Here, one or two or more materials selected from the following group can be used as the non-aqueous solvent. The group consists of propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and the like. As the supporting salt, _LiPF6 , _LiBF4 , LiClO4, _LiAsF6 , _{LiCF3SO3 , LiC4F9SO3} , LiN _{( CF3SO2} ) _{2 , LiC ( CF3SO2} ) _{3 ,} LiI, etc. One or two or more selected lithium compounds (lithium salts) can be used. In addition, it is assumed that a film-forming agent such as lithium bisoxalate borate (LiBOB) is added to the non-aqueous electrolyte.

As shown in FIG. 3, the adhesive layer 24 has a central space 24c disposed in the central portion of the laminate 20 as a space to be impregnated with the non-aqueous electrolyte, and a and a plurality of radial channels 24b communicating with each other. Each radial channel 24b may be separated by channel walls (walls) 24a. That is, the adhesive layer 24 has such walls 24a. Note that the walls 24a may be formed in such a state that impregnation with the non-aqueous electrolytic solution is more difficult than the radial flow paths 24b. It should be noted that FIG. 3 shows that the adhesive layer 24 is formed on the separator 22 .

In the laminate 20 having such a structure, the adhesive layer 24 has a plurality of radial channels 24b, which are channels in a radial pattern, and a central space 24c, as indicated by the size of the arrows in FIG. As a result, the non-aqueous electrolytic solution can be impregnated efficiently and evenly. As a result, in the non-aqueous secondary battery 1, the laminate 20 can be evenly impregnated with the non-aqueous electrolyte.

Here, the reason why the non-aqueous electrolytic solution is efficiently impregnated will be described. As the arrows in FIG. 4 illustrate the flow velocity in the radial flow path 24b, the cross-sectional area decreases and the velocity of the fluid increases as it progresses downstream (the non-aqueous electrolyte flows from left to right in FIG. 4). do. This is based on the theory of fluid mechanics, which states that the velocity of a fluid increases as it flows through a pipe with a decreasing cross-sectional area. Therefore, in the radial flow path 24b surrounded by the wall 24a, the electrode sheet (the positive electrode sheet 21 or the negative electrode sheet 23), and the separator 22, the flow velocity of the non-aqueous electrolyte increases toward the central space 24c, and impregnation is facilitated. Become.

Next, a comparative example will be described with reference to FIG. FIG. 5 is a schematic diagram showing a laminate housed in a case of a non-aqueous secondary battery according to a comparative example and how the laminate is impregnated with a non-aqueous electrolyte.

The laminate 120 according to the comparative example shown in FIG. An adhesive layer is formed. Note that illustration of this adhesive layer is omitted in FIG. The positive electrode sheet 121 has an active material-coated region 121a that constitutes an electrode, and a tab portion 121b that is an active material-uncoated region that protrudes from the active material-coated region 121a. The negative electrode sheet 123 also has an active material coated region 123a and a tab portion 123b.

In the comparative example, the non-aqueous electrolyte is injected into the case after the laminate 120, which is the source of the power generator, is placed in the case. A uniform adhesive layer is formed. Therefore, in the comparative example, impregnation of the non-aqueous electrolyte proceeds similarly from each of the four sides of the laminate 120 at the time of injection, and the central portion G of the laminate is impregnated last, so the central portion G of the laminate is non-aqueous electrolyzed. Insufficient liquid impregnation. In that case, the sodium salt of the negative electrode sheet 123 is pushed to the central portion, and a high resistance negative electrode film is formed in the central portion. As a result, in the power generating body generated from the laminate 120, resistance unevenness occurs between the central portion and the end portions, resulting in non-uniform electrochemical reaction.

On the other hand, in the laminate 20 shown in FIG. 3, as described above, the non-aqueous electrolyte can be impregnated smoothly up to the central portion (central space 24c) of the laminate 20 due to the presence of the radial flow paths 24b. . In particular, since the non-aqueous electrolyte flow path is radial, impregnation unevenness during liquid injection can be eliminated and the entire surface can be uniformly wetted. In addition, since the adhesive layer 24 has the radial flow paths 24b, the adhesive area is small. Therefore, in the power generating body produced from the laminate 20 of the present embodiment, the resistance unevenness in the surface direction can be reduced, and a uniform electrochemical reaction can be performed as compared with the comparative example.

Next, referring to FIG. 3 again, an example of the shape of the radial channel 24b will be described.
As shown in FIG. 3, the plurality of radial channels 24b can be arranged so that the cross-sectional area of each radial channel 24b on the end side (the outer edge side of the laminate 20) is substantially constant. In FIG. 3, as an example that satisfies the cross-sectional area conditions as described above, the radial flow paths 24b are shown to have the same thickness and a common width W. As shown in FIG.

As a result, in the case where the laminate 20 has a rectangular parallelepiped shape and the case 10 has a structure in which the non-aqueous electrolyte is allowed to penetrate substantially uniformly from each side (each side), the non-aqueous electrolyte is applied to the laminate 20 unevenly. can be impregnated without Such a structure can refer to, for example, a structure in which the volume density of the electrodes (mainly the positive electrode sheet 21 and the negative electrode sheet 23) occupying the cell is not high. Further, in this case, it is preferable that the cross-sectional area of each radial channel 24b on the side of the central space 24c is also constant.

Alternatively, the plurality of radial flow paths 24b may be arranged such that the radiation angle (angle θ in FIG. 4) of each radial flow path 24b on a plane perpendicular to the stacking direction of the laminate 20 is substantially constant. can. That is, the plurality of walls 24a can be arranged substantially uniformly in the circumferential direction within the plane of the laminate. In this case, in the case where the laminate 20 has a rectangular parallelepiped shape and has a structure in which the non-aqueous electrolyte penetrates substantially uniformly from each side in the case 10, the laminate is even more advantageous than the example in which the common width W is given. The body 20 can be evenly impregnated with the non-aqueous electrolyte. Also in this case, it is preferable that the cross-sectional area of each radial channel 24b on the side of the central space 24c is also constant.

Further, the adhesive layer 24 has been described as partitioning the adjacent radial channels 24b with the walls 24a made of adhesive. As a result, the radial flow paths 24b can be easily and reliably formed, and the laminate 20 can be impregnated with the non-aqueous electrolytic solution more evenly.

As described above, the walls 24a may be formed in such a state that impregnation with the non-aqueous electrolyte is more difficult than the radial flow paths 24b. Therefore, as an alternative structure to the structure in which the adhesive is applied only to the wall 24a, the following structure can be adopted.

That is, as an alternative structure, the adhesive layer 24 may have a wall 24a of high density adhesive between adjacent radial channels 24b, and each radial channel 24b may be separated by a lower density adhesive than the portion of the wall 24a. It is also possible to use an arranged flow path (a flow path in which the adhesive is distributed more sparsely than the portion of the wall 24a). Even in this case, since the radial flow path 24b is provided, the bonding area can be reduced. Even with such an alternative structure, the radial flow paths 24b can be easily formed, and the laminate 20 can be evenly impregnated with the non-aqueous electrolyte.

Further, in this case, the central space 24c can also be a space in which an adhesive having a lower density than the portion of the wall 24a is arranged, and the density of the adhesive in the central space 24c is equal to or higher than that of the radial channels 24b. It can be of low density. Thus, the central space 24c shown in FIG. 3 may be constructed so as not to be completely hollow. However, by leaving the central space 24c as a complete cavity, it is possible to further suppress non-aqueous electrolyte impregnation unevenness compared to the case where the adhesive is contained.

Moreover, in the adhesive layer 24 having any structure described above, it is preferable to apply the adhesive to the end portion (outer edge) of the laminate 20 . However, as described above, the radial flow path 24b continues to the end. This is because peeling and shrinkage from the ends can be suppressed by applying the adhesive to the ends.

(Embodiment 2)
The non-aqueous secondary battery according to Embodiment 2 will be described with reference to FIGS. 6 and 7, mainly focusing on differences from Embodiment 1, but various examples in Embodiment 1 can be applied. is. FIG. 6 is a schematic diagram showing an example of a non-aqueous secondary battery according to Embodiment 2 and a state of impregnation of a non-aqueous electrolyte in a laminate housed therein. FIG. 7 is a perspective view showing another example of the non-aqueous secondary battery according to Embodiment 2 and how the non-aqueous electrolyte is impregnated in the laminate housed therein.

In this embodiment, unlike the laminate 20 in the example of FIG. 3, the radial shape toward the end (outer edge) into which the non-aqueous electrolytic solution is difficult to enter is made denser than the radial shape toward the other end. In other words, in the present embodiment, the radial shape toward the end where the non-aqueous electrolytic solution can easily enter is made looser than the radial shape toward the other end.

For example, as shown in FIG. 6, the plurality of radial flow paths 24b have a cross-sectional area on the first end side of the radial flow paths 24b toward the first end (upper end in FIG. 6). It can be arranged so as to be wider than the cross-sectional area of the end portion side of the radial flow path toward the end portion other than the portion. Here, the first end is one of the ends of the laminate 20a in FIG. 6, and can refer to the upper end in FIG. In FIG. 6, as an example that satisfies the condition of the cross-sectional area as described above, the thickness of the radial flow path 24b is the same, and the width W2 on the first end side is made larger than the width W1 on the other end side. Illustrated.

That is, in the example of FIG. 6, the plurality of walls 24a are not arranged uniformly in the circumferential direction within the plane of the laminate, and the walls 24a toward the first end are arranged more sparsely than the walls 24a toward the other ends. ing. Of course, the walls 24a can be arranged with sparseness and denseness even in the wall 24a toward the end other than the first end, and the arrangement may be determined according to the ease with which the non-aqueous electrolytic solution can penetrate. For example, the walls 24a directed not only to the upper surface but also to the side can be arranged more sparsely than the walls 24a directed to the bottom.

Note that the laminate 20a shown in FIG. 6 has a structure in which the plurality of radial flow paths 24b in the laminate 20 shown in FIG. It is the same as the laminate 20 .

Moreover, as shown in FIG. 6, the laminate 20a is accommodated in a case 30 corresponding to the case 10. As shown in FIG. The case 30 has an injection port 31 for injecting a non-aqueous electrolyte into the laminate 20b. For example, the non-aqueous electrolyte can be injected into the case 30 by inserting the container 32 containing the non-aqueous electrolyte into the inlet 31 . After that, the container 32 is removed from the case 30, and the injection port 31 is sealed.

Such a structure is an example of a battery structure in which the laminate 20a allows more non-aqueous electrolyte to enter the case 30 from the first end than from the other ends. This is because the non-aqueous electrolyte is mainly injected from the container 32 from the upper side. This makes it more difficult for the non-aqueous electrolyte to impregnate.

The laminate 20a illustrated in FIG. 6 has such a structure that allows more non-aqueous electrolyte to enter the case 30 from the other end than from the first end. Even when the laminate 20a is a part of a non-aqueous secondary battery having such a structure, the existence of the plurality of radial flow paths 24b allows the non-aqueous electrolyte to be impregnated evenly. It will have an effect.

Here, an example in which the tab portion 21b of the positive electrode sheet and the tab portion 23b of the negative electrode sheet are provided on the first end side is given, but the positions of the tab portions are not limited to these. However, the tab portion is often bundled for each pole, and in that case, the non-aqueous electrolyte may be prevented from entering the laminate 20a. Therefore, in order to eliminate impregnation unevenness, it is necessary to determine the shape and arrangement of the plurality of radial flow paths 24b in consideration of not only the injection path of the non-aqueous electrolyte, but also the presence of such obstructing portions. It can be said that it is preferable.

Alternatively, in the plurality of radial flow paths 24b, the radiation angle of the radial flow paths toward the first end (upper end in FIG. 6) on a plane perpendicular to the stacking direction of the laminate 20a is the first end. It can also be arranged so as to be larger than the radiation angle of the radial flow path toward the end other than the end. A large radiation angle means that the radial flow path 24b is also wide. Also, the radiation angle here is an angle corresponding to the angle θ in FIG.

In the case where the laminate 20a has such a structure, it is possible to evenly impregnate the non-aqueous electrolytic solution due to the existence of the plurality of radial flow paths 24b, compared to the structure satisfying the cross-sectional area conditions described above. can. Of course, in this case as well, the effect of adopting a battery structure in which the laminate 20a allows more non-aqueous electrolyte to enter from the first end than from the other ends of the case 30 will be explained. there is

An example different from the example shown in FIG. 6 will be described with reference to FIG. In the example shown in FIG. 7 as well, the laminate 20b corresponding to the laminate 20a is accommodated in the case 30. As shown in FIG. A laminate 20b in FIG. 7 is obtained by modifying the laminate 20 in FIG. 3 or the laminate 20a in FIG. 6 so that the plurality of radial flow paths 24b have a structure that satisfies the following cross-sectional area conditions. are basically the same as those of the laminate 20 and the laminate 20a.

The non-aqueous secondary battery shown in FIG. 7 includes an insulating isolation member 33 that isolates the laminate 20b and the injection port 31 from each other. For example, the tab portion 21b of the positive electrode sheet and the tab portion 23b of the negative electrode sheet can be separated from each other along the horizontal direction of the laminate 20b, and the separation member 33 can be arranged in the resulting space. This space can be, for example, a space generated between the current collecting component of the tab portion 21b and the current collecting component of the tab portion 23b. The isolation member 33 can be fixed to the inner wall of the case or the like in the direction perpendicular to the plane of FIG.

In this way, the isolation member 33 can be arranged to cover (close) the end face of the laminate 20b, thereby playing a role of preventing the non-aqueous electrolyte from entering from above. Therefore, in the example of FIG. 7, compared to the example of FIG. 6, the non-aqueous electrolyte enters less from the upper side, and the non-aqueous electrolyte enters more from the bottom (and side). There is In particular, even if the non-aqueous secondary battery has a structure in which the non-aqueous electrolyte enters more from the bottom surface where the non-aqueous electrolyte is stored than from the upper side, the volume density of the electrode body and the separation member 33 may exist depending on the shape and arrangement of

The laminated body 20b is an example that employs an arrangement of a plurality of radial flow paths 24b to cope with such a case. It is upside down. That is, in the example of FIG. 7, the plurality of walls 24a are not arranged uniformly in the circumferential direction within the plane of the laminate, and the wall 24a facing the first end, which is the bottom surface side, is larger than the wall 24a facing the other end. distributed sparsely. Moreover, not only the bottom side but also the side wall 24a can be arranged more sparsely than the top side wall 24a.

Here, an example in which the tab portion 21b of the positive electrode sheet and the tab portion 23b of the negative electrode sheet are provided on the end portion side opposite to the first end portion, which is the bottom surface side, is given. The position of the tab portion is not limited to these, such as having it at one or more portions of the portion.

In addition, the laminate 20a or the laminate 20b may be wrapped with a tape such as PP (polypropylene) only at one end or more than once. and the permeation of the non-aqueous electrolyte may be prevented. Therefore, it can be said that it is preferable to determine the shape and arrangement of the plurality of radial flow paths 24b in consideration of the presence of such a tape in order to eliminate impregnation unevenness. For example, since it is difficult to permeate a region where a tape exists, a plurality of radial flow paths 24b can be formed to facilitate permeation at the end of the laminate on the side including that region.

(Embodiment 3)
As Embodiment 3, a manufacturing method applicable to manufacturing the non-aqueous secondary batteries according to Embodiments 1 and 2 will be described with reference to FIGS. 8 and 9. FIG. FIG. 8 is a flowchart for explaining an example of a method for manufacturing a non-aqueous secondary battery according to Embodiment 3. FIG. 9 is a top view showing an example of a manufacturing apparatus used in the manufacturing method of FIG. 8. FIG. Here, as a laminate housed in a non-aqueous secondary battery, a method for manufacturing the laminate 20b described with reference to FIG. 7 will be described as an example. Applicable.

The manufacturing method (hereinafter referred to as the present method) according to the present embodiment includes a lamination pressurization step (step S1), a cutting step (step S2), a lamination step (step S3), a pressurization step (step S4), and an impregnation step ( step S5). Each component of the non-aqueous secondary battery is as described in the first and second embodiments. Further, in steps S1 to S4, an adhesive layer is placed between each of the positive electrode sheet, the separator, and the negative electrode sheet, the positive electrode sheet, the separator, and the negative electrode sheet are laminated, and pressure is applied from both sides to generate the laminate 20b. It is an example of the laminated body production process. Incidentally, the tab portion can also be formed as appropriate by punching.

Schematically, in this method, first, in step S1, a laminate (hereinafter referred to as a first laminate) having separators arranged on both sides of a negative electrode sheet is formed, and in step S2, it is cut into unit lengths. . In this method, after that, in steps S3 and S4, a positive electrode sheet of the same unit length is further laminated on the cut laminated body of unit length (hereinafter referred to as a second laminated body) and pressed to form a laminated body 20b, In step S5, it is impregnated with a non-aqueous electrolyte.

In step S1, a long separator, a negative electrode sheet, and a separator, all of which are wound on a roll, are stacked in this order and passed through a pair of rollers to form a first laminate. By sandwiching and pressurizing the separator, the negative electrode sheet, and the first laminate composed of the separator from both sides with a pair of rollers, the separator, the negative electrode sheet, and the separator can be bonded to each other.

For this adhesion, an adhesive is applied to the entire area where the adhesive layer 24 is to be formed when passing through at least a pair of rollers. For example, on the separator used in step S1, an adhesive (adhesive binder) that becomes the adhesive layer 24 can be placed on the entire surface of both sides or the entire surface of the negative electrode sheet. Alternatively, the adhesive may be placed on the entire surface of the negative electrode sheet on the separator side. However, at this stage, the adhesive layer 24 including the radial channels 24b and the central space 24c is not yet formed. Such a pressurizing process and the pressurizing process of step S4 described later can also be referred to as a pressurizing/bonding process, and heating can also be performed during pressurization.

Specifically, referring to FIG. 9, a manufacturing apparatus equipped with a pair of rollers and a pressurizing/bonding process using the apparatus will be described. Although only the upper roller 41 is shown in FIG. 9, rollers are arranged below the roller 41 so as to sandwich the laminate 20b. In addition, although not shown, the manufacturing apparatus includes a roller around which each member is wound, a conveying roller that conveys each member, a tension mechanism that pulls the laminate after passing through a pair of rollers, and tension generated by the tension mechanism and each A control may be provided to control the speed of rotation of the rollers.

In the example of FIG. 9, in the manufacturing apparatus, the separator, the negative electrode sheet, and the separator wound on the respective rolls are pulled out, and the roller 41 rotates around the roller shaft 42 together with the other rollers below in the direction of the arrow in the figure. By doing so, the first laminate in which both sides of the negative electrode sheet are sandwiched between the separators is passed while being pressed.

At this time, in the first laminate, as a space impregnated with the non-aqueous electrolyte, a central space 24c disposed in the central portion of the laminate 20b and a plurality of radial flow paths communicating from the central space 24c toward the end portion. 24b is formed. That is, the present method includes such an adhesive layer forming step.

In particular, in the adhesive layer forming step to which the example of FIG. 9 is applied, in step S1, the adhesive is applied (over the entire surface) to the entire area between each of the negative electrode sheet and the two separators arranged on both sides thereof. Including the step of applying. Then, this adhesive layer forming step can include a step of applying pressure from both sides of the laminated member (here, the first laminated body) in a state where the adhesive is applied with a pressure member as described below.

The pressurizing member used here is, as exemplified by the roller 41 in FIG. 9, a pressurizing member provided with convex portions 41a in the regions that become the walls 24a of the adjacent radial flow paths 24b. A flat portion 41b is formed except for the convex portion 41a. The roller 41 can be a so-called gravure roll. Even when a gravure roll is employed, only one roller may be provided with the convex portion 41a, or both rollers may be provided with the convex portion 41a.

In the adhesive layer forming step, the adjacent radial flow paths 24b are partitioned by walls 24a made of a high-density adhesive, and each radial flow path 24b is lower than the wall 24a. The adhesive layer 24 is formed so as to form a flow path in which the adhesive of high density is arranged. The adhesive has a high density in the region pressed by the convex portion 41a, and has a low density in the other regions. By such adhesion in step S1, the negative electrode sheet and the separator are bonded together in a state where the adhesive layer 24 including the walls 24a, the radial channels 24b, and the central space 24c is formed.

Thereafter, in step S2, for example, the negative electrode sheet is cut at the position indicated by the dashed line in FIG. 9 to complete a second laminate having a unit length in which both sides of the negative electrode sheet are sandwiched between separators. Note that the unit length refers to the length when the non-aqueous secondary battery 1 is accommodated. The cutting can be performed by a cutting device provided after the pair of rollers have passed through, but can also be performed by using a separate cutting device after winding the laminate that has passed through the pair of rollers. Note that the description will be made on the premise that the width of the first laminate is the unit width for housing in the non-aqueous secondary battery 1, but the width of the first laminate may also be wider than the unit width. In step S2, it is preferable to complete the second laminate by cutting the first laminate into unit lengths and unit widths.

In step S3, an adhesive layer is arranged between the positive electrode sheet and the second laminate, and the positive electrode sheet and the second laminate are laminated to form a laminate (hereinafter referred to as the third laminate). The third laminate can be configured by laminating a plurality of sets of positive electrode sheets and second laminates. Further, the positive electrode sheet used in step S3 may be a long sheet originally wound on a roll and cut into unit lengths or unit lengths and unit widths.

At the time of lamination in step S3, if the adhesive is applied to the entire surface of the negative electrode sheet side of the separator used in step S1 and not to the other surface side, first, in step S3, the entire surface of the positive electrode sheet side of the separator or the positive electrode sheet is applied. An adhesive that will become the adhesive layer 24 is applied to the entire surface of the sheet on the separator side. However, at this stage, the adhesive layer 24 including the radial channels 24b and the central space 24c is not formed between the positive electrode sheet and the separator.

In step S4, which is executed after the processing in step S3, the positive electrode sheet and the separator are adhered to form a laminate 20b by sandwiching and pressurizing the third laminate from both sides with pressure members. The pressurizing member used here is a pressurizing member provided with a convex portion 41a in the region serving as the wall 24a of the adjacent radial flow passages 24b as illustrated in FIG. A pair of rollers illustrated in FIG. 9 can be used as this pressure member, but it is preferable to use a pair of pressure plates for ease of manufacture.

When pressurizing, the third laminate to be pressurized is aligned with the radial flow paths 24b and the central space 24c formed in the adhesive layer 24 between the negative electrode sheet and the separator. It is preferable to form the second laminate and the positive electrode sheet so as to overlap each other. If such alignment is not performed, the pressure should be reduced or the heating temperature should be adjusted so that the radial flow path 24b between the negative electrode sheet and the separator is not completely blocked. You should go.

According to this method, the adhesive layer 24 having a plurality of radial channels 24b and a central space 24c formed between the positive electrode sheet, the negative electrode sheet, and the separator members is efficiently impregnated with the non-aqueous electrolyte. can be performed, and the laminate 20b can be evenly impregnated with the non-aqueous electrolyte.

In step S5, which is executed after the process in step S4, the pressurized laminate 20b is housed in the case 30, and the laminate 20b is impregnated with a non-aqueous electrolyte. In this method, the radial channels 24b and the central space 24c can be easily formed between the separator and the negative electrode sheet and between the separator and the positive electrode sheet in steps S1 and S4, respectively, and the formed radial channels In step S5, the laminate 20b can be impregnated with the non-aqueous electrolyte more evenly by means of the non-aqueous electrolyte 24b and the central space 24c. After that, the container 32 is removed, and post-processing such as sealing the injection port 31 is performed. This post-processing does not matter in this embodiment.

Also, the adhesive layer forming process can be replaced by the following alternative process. That is, in both steps S1 and S3, the alternative adhesive layer forming step is a step of applying an adhesive as the adhesive layer 24 to the regions that will be the walls 24a of the adjacent radial channels 24b in the plurality of radial channels 24b. can be included. Then, in the pressing process in step S1, a pair of smooth rollers are used to form a plurality of walls 24a in the adhesive layer 24, and adjacent walls 24a form a radial flow path 24b and a central space 24c. In this state, the negative electrode sheet and the separator are bonded together. In the subsequent pressing step of step S4, a pair of smooth rollers are used to form a plurality of walls 24a in the adhesive layer 24, and adjacent walls 24a form a radial flow path 24b and a central space 24c. Then, the positive electrode sheet and the separator are bonded together.

In particular, in such an alternative process, it is possible to easily form a structure in which the adhesive layer 24 separates adjacent radial channels 24b with adhesive walls 24a, and the radial channels 24b are defined as spaces. It is possible to easily form even a structure that As a result, the radial flow paths 24b can be easily and reliably formed, and the laminate can be evenly impregnated with the electrolytic solution.

In the above description, it is assumed that a long laminate is cut into unit lengths. It is also possible to laminate and adhere under pressure. Also in this case, a pair of rollers can be used, but other pressure members such as a pair of pressure plates can also be used. When using a pair of pressurizing plates, it is sufficient that they have a convex portion such as the convex portion 41a. Only one of the pair of pressurizing plates may be provided with a convex portion such as the convex portion 41a, or both of the pressure plates may be provided with such a convex portion.

Also, the adhesive layer 24 including the radial channels 24b and the central space 24c may not be formed between the positive electrode sheet and the separator. For example, in step S4 of FIG. 8, by using a pair of rollers or pressure plates having a flat periphery, a laminate having such a configuration can be formed. Alternatively, when adopting the above alternative process, only in the process of step S1, the step of applying the adhesive as the adhesive layer 24 to the regions that will be the walls 24a of the adjacent radial channels 24b in the plurality of radial channels 24b. and applying an adhesive to the entire surface in the process of step S3, such a laminate can be formed.

In either case, the adhesive layer 24 having a plurality of radial channels 24b and a central space 24c formed between the members of the negative electrode sheet and the separator enables efficient impregnation with the non-aqueous electrolyte. , the non-aqueous electrolyte can be evenly impregnated between the separator and the negative electrode sheet of the laminate 20b. In particular, even when the third laminate is configured by laminating many sets of the positive electrode sheet and the second laminate, the radial flow paths 24b and the like can be formed between the negative electrode sheet and the separator first. Therefore, the non-aqueous electrolyte can be evenly impregnated there.

In a similar manner, the adhesive layer 24 including the radial flow paths 24b and the central space 24c is formed only between the positive electrode sheet and the separator, and the radial flow paths 24b and the central space 24c are formed between the negative electrode sheet and the separator. It is also possible not to form the adhesive layer 24 which comprises. The manufacturing procedure may be carried out by, for example, replacing the positive electrode sheet and the negative electrode sheet in the above-described procedure.

(other embodiments, etc.)
In addition, the present invention is not limited to the first to third embodiments, and may be implemented by appropriately combining the respective embodiments, and may be changed as appropriate without departing from the scope of the invention. . For example, the shape and material of each member described in Embodiments 1 to 3, or the manufacturing method is not limited to those exemplified, and can function as a secondary battery, or can manufacture such a secondary battery. Any method is acceptable. In Embodiments 1 to 3, the non-aqueous secondary battery was taken as an example, but the electrolyte is not limited to the non-aqueous electrolyte, and in Embodiments 1 to 3, a positive electrode sheet, a separator, and a negative electrode sheet are laminated. Any secondary battery having a laminate can be applied.

For example, in Embodiments 1 to 3, an example in which a power generation body having a laminated structure is housed in a case has been described, but a wound body (power generation body having a wound structure) can also be employed as the power generation body. This wound body is obtained by winding a laminated body in which a separator, a positive electrode sheet, a separator, a negative electrode sheet, and a separator are laminated, for example. This wound body can be accommodated in a case with the ends in the winding axial direction oriented vertically or horizontally, and one or a plurality of wound bodies can be accommodated in the case. In the case of the wound body stored in this way, the electrolytic solution is impregnated from the vertical direction or the horizontal direction. When the ends are housed in the vertical direction, there is no impregnation of the electrolytic solution from the lateral direction, but if radial flow paths as described above are provided at the upper and lower ends, the impregnation of the electrolytic solution can be promoted. In addition, when the ends are accommodated in the horizontal direction, there is no impregnation of the electrolytic solution from above and below, but if the radial flow paths as described above are provided at the right and left ends, the impregnation of the electrolytic solution can be promoted. can. Therefore, even when the wound body is accommodated with the ends in the winding axial direction in the vertical direction or the horizontal direction, the resistance unevenness in the present embodiment is reduced in the same manner as in the case where the power generation body with the laminated structure is adopted. It can be said that it has the effect of making

REFERENCE SIGNS LIST 1 non-aqueous secondary battery 10, 30 case 11 lid 12 negative pole 13 positive pole 20, 20a, 20b laminate 21 positive electrode sheet 21a positive electrode side active material coated region 21b positive electrode side tab portion 22 separator 23 negative electrode sheet 23a Negative electrode side active material coating region 23b Negative electrode side tab portion 24 Adhesive layer 24a Wall 24b Radial channel 24c Central space 31 Liquid inlet 32 Container 33 Separating member 41 Roller 41a Convex portion 41b Flat portion 42 Roller shaft

Claims (10)

comprising a laminate and a case for housing the laminate,
The laminate includes a positive electrode sheet, a negative electrode sheet, a separator sandwiched between the positive electrode sheet and the negative electrode sheet, and an adhesive layer formed by bonding the positive electrode sheet, the separator, and the negative electrode sheet together. and
The adhesive layer at least between the separator and the negative electrode sheet or between the separator and the positive electrode sheet has a central space disposed in the central portion of the laminate as a space to be impregnated with an electrolytic solution, and a plurality of radial channels communicating toward the end,
secondary battery. The plurality of radial channels are arranged so that the radiation angle of each radial channel on a plane perpendicular to the stacking direction of the laminate is substantially constant.
The secondary battery according to claim 1. The plurality of radial channels are arranged so that the cross-sectional area of each radial channel on the end side is substantially constant,
The secondary battery according to claim 1. In the plurality of radial flow paths, the radial angle of the radial flow paths toward a first end, which is one of the ends, on a plane perpendicular to the stacking direction of the laminate is equal to the first end. is arranged to be greater than the radial angle of the radial flow path toward the end other than
The secondary battery according to claim 1. In the plurality of radial flow paths, the cross-sectional area of the radial flow path toward the first end, which is one of the ends, on the first end side is toward the end other than the first end. It is arranged so as to be wider than the cross-sectional area on the end side of the radial flow channel,
The secondary battery according to claim 1. the adhesive layer at least between the separator and the negative electrode sheet or between the separator and the positive electrode sheet, wherein adjacent radial channels are partitioned by adhesive walls;
The secondary battery according to any one of claims 1-5. wherein the adhesive layer at least between the separator and the negative electrode sheet or between the separator and the positive electrode sheet is partitioned by a high-density adhesive wall between adjacent radial channels;
each radial channel is a channel in which an adhesive having a lower density than the wall portion is disposed;
The secondary battery according to any one of claims 1-5. A secondary battery for manufacturing a secondary battery comprising: a laminate having a positive electrode sheet, a negative electrode sheet, and a separator sandwiched between the positive electrode sheet and the negative electrode sheet; and a case accommodating the laminate. A manufacturing method comprising:
Lamination in which an adhesive layer is arranged between each of the positive electrode sheet, the separator, and the negative electrode sheet, the positive electrode sheet, the separator, and the negative electrode sheet are laminated, and pressure is applied from both sides to form the laminate. a body generation process;
An impregnation step of housing the laminate produced by the laminate producing step in the case and impregnating the laminate with an electrolytic solution;
with
At least the separator and the negative electrode have a central space disposed in the central portion of the laminate and a plurality of radial channels communicating from the central space toward the end portions as spaces impregnated with the electrolytic solution. An adhesive layer forming step of forming the adhesive layer between sheets or between the separator and the positive electrode sheet,
A secondary battery manufacturing method. In the adhesive layer forming step, as the adhesive layer disposed at least between the separator and the negative electrode sheet or between the separator and the positive electrode sheet, a region serving as a wall of adjacent radial channels in the plurality of radial channels applying an adhesive to the
The secondary battery manufacturing method according to claim 8 . The adhesive layer forming step includes:
a step of applying an adhesive to the entire area where the adhesive layer is to be formed;
In the step of forming the adhesive layer disposed at least between the separator and the negative electrode sheet or between the separator and the positive electrode sheet, a convex portion is formed on a region that becomes a wall of adjacent radial channels in the plurality of radial channels. a step of applying pressure with a pressure member provided with
Adjacent radial channels are separated by walls made of a high-density adhesive, and at least the separator and forming the adhesive layer disposed between the negative electrode sheets or between the separator and the positive electrode sheet;
The secondary battery manufacturing method according to claim 8 .

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