Storage battery

Abstract

To provide a storage battery that has excellent conformability to both unevenness and expansion / contraction.SOLUTION: A storage battery 1 includes a stack 2, a pair of end plates, a pressurizing mechanism 4 that pressurizes the end plates, and an elastic mechanism disposed between at least one of the pair of end plates and the stack. The elastic mechanism includes a first elastic body having a stress-strain curve in which the relationship between stress and distortion is linear as distortion increases, and a second elastic body having a stress-strain curve in which the relationship between stress and distortion is nonlinear and the elastic modulus increases as distortion increases. The first elastic body is disposed between the second elastic body and the stack.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a storage battery.

Background Art

[0002] As a storage battery, one having a pressurized structure is known. As the pressurized structure, a structure using a pair of end plates is known. In such a storage battery, the battery portion is sandwiched between a pair of end plates. A load is applied to the pair of end plates so that the battery portion is compressed. Thereby, the battery portion is compressed via the pair of end plates.

[0003] In relation to the above, for example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2009-99383) discloses a pressurized structure of a laminate which is a laminate formed by laminating specific power generation elements or power storage elements, the pressurized structure including a pair of end plates positioned above and below the laminate, and a plate-like elastic body that sandwiches the end plates from above and below and pressurizes the laminate in the lamination direction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, among storage batteries, there are those that require a high pressing force. For example, in order to realize desired battery characteristics, an all-solid-state battery needs to be pressed at a higher pressure than other storage batteries. At this time, it is desired that the battery portion is uniformly pressed. However, there may be unevenness on the surface of the battery portion. In a storage battery that requires a high pressing force, if there are unevenness on the surface of the battery portion, the end plate may tilt, making it difficult to apply pressure uniformly.

[0006] Therefore, the present inventors have considered disposing an elastic body capable of absorbing unevenness between the end plate and the battery portion. By using a specific elastic body, the unevenness can be absorbed and the inclination of the end plate can be prevented. As a result, a uniform pressure can be applied regardless of the unevenness. In the following description, the property of being able to apply a uniform pressure even when there are unevenness may be referred to as "unevenness absorbability".

[0007] On the other hand, among storage batteries, there are those that expand and contract significantly with charge and discharge. For example, in a all-solid-state battery using metallic lithium as a negative electrode active material, the thickness of the battery portion changes greatly with charge and discharge. In such a storage battery, it is desired that a desired pressure is applied to the battery portion both during expansion and contraction. In the following description, the property of being able to apply a desired pressure to the battery portion both during expansion and contraction may sometimes be referred to as "expansion and contraction followability".

[0008] The present inventors examined whether there is an elastic body that is excellent in both unevenness absorbability and expansion and contraction followability. However, an elastic body excellent in unevenness absorbability was likely to be lacking in expansion and contraction followability. On the other hand, an elastic body excellent in expansion and contraction followability had problems in unevenness absorbability. That is, it was difficult to achieve both properties.

[0009] Therefore, an object of the present invention is to provide a storage battery that is excellent in both unevenness followability and expansion and contraction followability.

Means for Solving the Problems

[0010] In one aspect, a storage battery according to the present invention includes a laminate having an electrolyte layer, a positive electrode layer, and a negative electrode layer, a pair of end plates disposed so as to sandwich the laminate in the stacking direction, a pressing mechanism for pressing the end plates, and an elastic mechanism disposed between at least one of the pair of end plates and the laminate. The elastic mechanism includes a first elastic body having a stress-strain curve such that the relationship between stress and strain is linear when the strain increases, and a second elastic body having a stress-strain curve such that the relationship between stress and strain is non-linear and the elastic modulus increases as the strain increases. The first elastic body is disposed between the second elastic body and the laminate.

Advantages of the Invention

[0011] According to the present invention, a storage battery excellent in both unevenness followability and expansion / contraction followability is provided.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8A

Figure 8B

Figure 9A

Figure 9B

Figure 10A

Figure 10B

Figure 10C

Figure 11

Figure 12

MODE FOR CARRYING OUT THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0014] (1) First Embodiment FIG. 1 is a schematic cross-sectional view showing a storage battery 1 according to the first embodiment.

[0015] The storage battery 1 according to the present embodiment is, for example, an all-solid-state battery. In this specification, the "all-solid-state battery" is a secondary battery in which the electrolyte layer, the positive electrode layer, and the negative electrode layer are all substantially solid. Each layer only needs to be "substantially" solid, and a small amount of liquid substance may be used even if it is small. In an all-solid-state battery, in order to realize the functions as a desired battery, the battery portion needs to be pressurized at a high pressure.

[0016] The storage battery 1 according to this embodiment is preferably an all-solid-state battery using metallic lithium as a negative electrode active material. In such an all-solid-state battery, metallic lithium is deposited on the negative electrode side during charging. On the other hand, during discharging, the metallic lithium on the negative electrode side moves to the positive electrode side and is occluded in the positive electrode. That is, with charging and discharging, deposition and disappearance of metallic lithium are repeated on the negative electrode side. Therefore, it greatly expands and contracts with charging and discharging. Accordingly, unevenness absorbability and expansion / contraction followability are particularly required.

[0017] As shown in FIG. 1, the storage battery 1 includes a laminate 2, a pair of end plates (3-1 and 3-2), a pressurizing mechanism 4, an elastic mechanism 5, and a frame body 11.

[0018] The laminate 2 is a part that realizes the function as a battery. The laminate 2 has an electrolyte layer, a positive electrode layer, and a negative electrode layer. The laminate 2 is configured such that its thickness changes with charging and discharging.

[0019] FIG. 2 is a schematic cross-sectional view showing an example of the configuration of the laminate 2. In the example shown in FIG. 2, the laminate 2 has a plurality of cells (2-1 to 2-n) laminated along the lamination direction. And each cell (2-1 to 2-n) has an electrolyte layer 7, a positive electrode layer 8, and a negative electrode layer 6. The positive electrode layer 8 and the negative electrode layer 6 are arranged so as to sandwich the electrolyte layer 7 in the lamination direction. The plurality of cells (2-1 to 2-n) are laminated such that the positive electrode layer 8 sides face the same side (the upper side in FIG. 2).

[0020] Each cell (2-1 to 2-n) further has an insulating layer 9 and a laminate material 10. The insulating layer 9 is arranged so as to surround the laminated structure composed of the electrolyte layer 7, the positive electrode layer 8, and the negative electrode layer 6. The laminate material 10 seals the electrolyte layer 7, the positive electrode layer 8, the negative electrode layer 6, and the insulating layer 9.

[0021] The above is the configuration of the laminate 2. In the example shown in FIG. 2, the laminate 2 includes a plurality of cells (2-1 to 2-n), but the number of cells included in the laminate 2 may be single.

[0022] Referring to FIG. 1 again, a pair of end plates (3-1 and 3-2) will be described. The pair of end plates (3-1 and 3-2) are arranged so as to sandwich the laminate 2 in the stacking direction. Each end plate (3-1 and 3-2) is wider than the laminate 2. That is, when viewed along the stacking direction, the outer peripheral ends of each end plate (3-1 and 3-2) are located outside the outer peripheral ends of the laminate 2.

[0023] The pressing mechanism 4 is configured to press the pair of end plates (3-1 and 3-2). The pressing mechanism 4 is realized, for example, by bolts and nuts configured to fasten the pair of end plates (3-1 and 3-2). Due to the pressing mechanism 4, a force that causes the pair of end plates (3-1 and 3-2) to approach each other is applied between the pair of end plates (3-1 and 3-2).

[0024] The elastic mechanism 5 is arranged between at least one of the pair of end plates (3-1 and 3-2) and the laminate 2. In the example shown in FIG. 1, the elastic mechanism 5 is arranged between the end plate 3-1 and the laminate 2.

[0025] The elastic mechanism 5 has a first elastic body 5-1 and a second elastic body 5-2. The first elastic body 5-1 is arranged between the second elastic body 5-2 and the laminate 2. That is, in the elastic mechanism 5, the first elastic body 5-1 is arranged on the laminate 2 side, and the second elastic body 5-2 is arranged on the end plate 3-1 side. The first elastic body 5-1 is in contact with the laminate 2.

[0026] The first elastic body 5-1 and the second elastic body 5-2 have different stress-strain curves. This will be specifically described below.

[0027] Figure 3 is a graph showing an example of the stress-strain curve of the first elastic body 5-1. In Figure 3, a load is applied to the first elastic body 5-1 to compress it until a predetermined load (4 MPa) is reached, and then the stress-strain curve when the load is decreased is shown. As shown in Figure 3, the first elastic body 5-1 has a stress-strain curve such that the relationship between stress and strain is linear when the strain increases (see arrow "a" in the figure). That is, when the strain (stress) increases, the elastic modulus (the slope in the stress-strain curve) of the first elastic body 5-1 is constant.

[0028] In this specification, "the relationship between stress and strain is linear" means that the R2 value when linearly approximated in the range of 0 to 4 MPa is 0.9 or more. This value is preferably 0.95 or more, more preferably 0.98 or more.

[0029] In the example shown in Figure 3, when the strain (stress) decreases (see arrow "b" in the figure), the relationship between stress and strain is non-linear. Specifically, it is a stress-strain curve such that the elastic modulus (the slope of the stress-strain curve) decreases as the strain decreases.

[0030] In this specification, "the relationship between stress and strain is non-linear" means that the R2 value when linearly approximated in the range of 0 to 4 MPa is less than 0.9. This value is preferably less than 0.8, more preferably less than 0.7.

[0031] On the other hand, Figure 4 is a graph showing an example of the stress-strain curve of the second elastic body 5-2. Similar to Figure 3, in Figure 4, a load is applied to the second elastic body 5-2 to compress it until a predetermined load (4 MPa) is reached, and then the stress-strain curve when the load is decreased is shown. As shown in Figure 4, the stress-strain curve of the second elastic body 5-2 is non-linear both when the strain increases and when it decreases. Specifically, it has a stress-strain curve such that the elastic modulus increases as the strain increases.

[0032] Next, the frame body 11 will be described. As shown in FIG. 1, the frame body 11 is arranged so as to surround the first elastic body 5-1 and the second elastic body 5-2 in the plane direction (a direction perpendicular to the stacking direction). The frame body 11 is configured to suppress the swelling of the first elastic body 5-1 and the second elastic body 5-2 in the plane direction. In the example shown in FIG. 1, the frame body 11 has a flat plate portion 13 and side wall portions 14. The flat plate portion 13 is a flat plate-like portion and is arranged so as to cover the surface of the second elastic body 5-2. The side wall portions 14 are coupled to the outer peripheral end portions of the flat plate portion 13 and extend from the outer peripheral end portions in the stacking direction. The first elastic body 5-1 and the second elastic body 5-2 are surrounded by the side wall portions 14 in the plane direction. That is, the swelling of the first elastic body 5-1 and the second elastic body 5-2 is regulated in the plane direction by the side wall portions 14.

[0033] The above is the configuration of the storage battery 1 according to the present embodiment. According to the configuration as described above, as the elastic mechanism 5, two types of elastic bodies each having a specific stress-strain curve are used, so that both the unevenness absorption property and the expansion / contraction followability can be achieved.

[0034] Specifically, by using the first elastic body 5-1, the unevenness absorption property is improved. That is, even when unevenness (for example, unevenness of about several tens of μm) is generated on the surface of the laminate 2, it becomes possible to uniformly apply pressure to the laminate 2. On the other hand, when only the first elastic body 5-1 is used, it is difficult to obtain the desired expansion / contraction followability. In particular, as shown in FIG. 3, when the first elastic body 5-1 has a stress-strain curve such that the elastic modulus (slope) decreases as the strain decreases, when the laminate 2 contracts, the pressure applied from the first elastic body 5-1 to the laminate 2 significantly decreases. As a result, it becomes difficult to obtain the desired functions as a battery in the laminate 2.

[0035] On the other hand, by using the second elastic body 5-2 in addition to the first elastic body 5-1, the expansion and contraction followability is improved. That is, by using the second elastic body 5-2, even when the laminate 2 contracts, a certain amount of pressure can be applied to the laminate 2 by the reaction force of the second elastic body 5-2. That is, it is possible to achieve both unevenness absorbability and expansion and contraction followability. In addition, when only the second elastic body 5-2 is used and the first elastic body 5-1 is missing, the unevenness absorbability decreases. By using the first elastic body 5-1 and the second elastic body 5-2 in combination, it is possible to achieve both unevenness absorbability and expansion and contraction followability.

[0036] Furthermore, in the present embodiment, since the frame body 11 is provided, it is possible to apply pressure uniformly to the laminate 2 also in the plane direction. If the frame body 11 is missing, the first elastic body 5-1 spreads in the plane direction, and the pressure is dispersed at its outer peripheral portion. As a result, it becomes difficult to apply pressure to the laminate 2 at the outer peripheral portion in the plane direction. On the other hand, by providing the frame body 11, it is possible to avoid the dispersion of pressure at the outer peripheral portion in the plane direction. That is, it becomes possible to apply pressure uniformly to the laminate 2 in the plane direction.

[0037] Note that FIG. 5 is a graph showing the stress-strain curve of the first elastic body 5-1 when the second elastic body 5-2 is not used and the first elastic body 5-1 and the frame body 11 are used. Further, FIG. 6 is a graph showing the stress-strain curve of the elastic mechanism 5 in the storage battery 1 having the first elastic body 5-1, the second elastic body 5-2, and the frame body 11. That is, it is a graph showing the stress-strain curve of the elastic mechanism 5 in the storage battery 1 having the configuration according to the present embodiment shown in FIG. As shown in FIG. 5, when the second elastic body 5-2 is missing, the stress-strain curve during the reduction of strain (during the contraction of the laminate 2, middle, arrow "b") is non-linear. This means that when the laminate 2 contracts rapidly, it becomes difficult for pressure to be applied. On the other hand, as shown in FIG. 6, when the second elastic body 5-2 is used in addition to the first elastic body 5-1, the difference in the stress-strain curve is reduced between when the strain increases (during expansion, arrow a in the figure) and when the strain decreases (during contraction, arrow b in the figure). This means that a desired pressure can be applied to the laminate 2 during contraction as well as during expansion.

[0038] As described above, according to the present embodiment, by using the first elastic body 5-1 and the second elastic body 5-2 in combination, it is possible to achieve both unevenness absorbability and expansion / contraction followability. Furthermore, by using the frame body 11, it becomes possible to apply pressure uniformly in the plane direction.

[0039] Also, due to the above-described effects, improvement in rapid charge / discharge characteristics and cycle characteristics can also be expected. For example, when the storage battery 1 is an all-solid-state battery using metallic lithium as the negative electrode active material, the way pressure is applied affects the rapid charge / discharge characteristics and cycle characteristics. According to the present embodiment, as a result of the improvement in unevenness absorbability, expansion / contraction followability, and pressure uniformity in the plane direction, the rapid charge / discharge characteristics and cycle characteristics can also be improved.

[0040] Subsequently, a preferred embodiment will be described.

[0041] It is preferable that the final strain of the second elastic body 5-2 is larger than the final strain of the first elastic body 5-1. The "final strain" referred to here means the magnitude of the strain of each elastic body when the thickness of the laminate 2 becomes maximum during charge and discharge. According to such a configuration, the second elastic body 5-2 will be more strained during the expansion of the laminate 2, and the expansion and contraction followability will be further improved.

[0042] Also, it is preferable that the strain at the inflection point in the stress-strain curve of the second elastic body 5-2 is larger than the final strain of the first elastic body 5-1. The "inflection point" referred to here means the point at which the elastic modulus (slope) changes in the stress-strain curve of the second elastic body 5-2 when the strain increases (see, for example, FIG. 4). When the slope in the stress-strain curve gradually changes with the change in strain, the point at which the change amount of the slope per unit strain is the largest can be obtained as the "inflection point". By adopting such a configuration, the pressure followability is improved near the target pressing force. If the strain at the inflection point in the stress-strain curve of the second elastic body 5-2 is smaller than the final strain of the first elastic body 5-1, the second elastic body 5-2 will have physical properties close to those of a rigid body just by applying a slight load. Therefore, it becomes difficult for the second elastic body 5-2 to function as an elastic body, and it may be difficult to obtain the desired expansion and contraction followability.

[0043] The pressing mechanism 4 preferably applies a load such that the second elastic body 5-2 is compressed with a load exceeding its inflection point. For example, the second elastic body 5-2 is preferably compressed so that a load of 1.5 to 4 MPa, preferably 2 to 3 MPa, is applied during charge and discharge.

[0044] Also, as shown in FIG. 1, it is preferable that the first elastic body 5-1 and the second elastic body 5-2 are in contact with each other. According to such a configuration, the reaction force from the second elastic body 5-2 is directly transmitted to the first elastic body 5-1. As a result, it becomes easier to apply pressure to the laminate 2 through the first elastic body 5-1, and the expansion and contraction followability is improved.

[0045] Further, it is preferable that the laminate 2 is arranged such that the positive electrode layer 8 faces the elastic mechanism 5 side. Specifically, it is preferable that the surface on the positive electrode layer 8 side in the laminate 2 is in contact with the first elastic body 5-1. Concavities and convexities of about several tens of micrometers may be formed on the surface of the positive electrode layer 8. Therefore, it is inherently difficult to apply pressure uniformly to the surface of the positive electrode layer 8. However, according to the present embodiment, since the unevenness absorbability is improved, even when there are concavities and convexities on the surface of the positive electrode layer 8, pressure can be applied to the positive electrode layer 8 uniformly.

[0046] The specific material of the first elastic body 5-1 is not particularly limited. For example, as the first elastic body 5-1, those having a dense structure can be preferably used. Further, as the first elastic body 5-1, those containing silicon rubber can be used.

[0047] The specific material of the second elastic body 5-2 is not particularly limited. For example, as the second elastic body 5-2, those having a porous structure (for example, foam-like) can be used. For example, as the second elastic body 5-2, those containing fluorine-based rubber can be used.

[0048] (2) Second Embodiment Subsequently, the second embodiment will be described. Regarding the points where the same configuration as that of the first embodiment can be adopted, detailed description will be omitted.

[0049] FIG. 7 is a schematic view showing the storage battery 1 according to the present embodiment. In the present embodiment, a plurality of laminates 2 are arranged along the lamination direction. And the elastic mechanism 5 is also arranged between adjacent laminates 2.

[0050] According to the present embodiment, since the elastic mechanism 5 is also provided between adjacent laminates 2, it becomes possible to pressurize each laminate 2 more uniformly.

[0051] (3) Third Embodiment Subsequently, the third embodiment will be described. Regarding the points where the same configuration as that of the above-described embodiment can be adopted, detailed description will be omitted.

[0052] FIG. 8A is a schematic view showing the storage battery 1 according to the present embodiment. In the present embodiment, the configuration of the frame body 11 is different from that of the above-described embodiment. Specifically, the frame body 11 is annular. That is, the frame body 11 does not have the flat plate portion 13 (see FIG. 1) and is constituted only by the side wall portion 14.

[0053] As in the present embodiment, the flat plate portion 13 in the frame body 11 is not essential, and the frame body 11 may be annular. Even if such a configuration is adopted, the same operational effects as those of the above-described embodiment can be obtained.

[0054] Note that FIG. 8B is a view showing a modification of the present embodiment. In this modification, as in the second embodiment, a plurality of laminate bodies 2 are arranged. And the elastic mechanism 5 is arranged between adjacent laminate bodies 2. That is, a plurality of elastic mechanisms 5 are arranged. The frame bodies 11 are also arranged in plurality corresponding to the plurality of elastic mechanisms 5.

[0055] (4) Fourth Embodiment Subsequently, the fourth embodiment will be described. The detailed description will be omitted for the points where the same configuration as that of the above-described embodiment can be adopted.

[0056] FIG. 9A is a schematic view showing the storage battery 1 according to the present embodiment. In the present embodiment, the frame body 11 is arranged between the first elastic body 5-1 and the second elastic body 5-2. Specifically, the frame body 11 has the flat plate portion 13 and the side wall portion 14. The flat plate portion 13 is arranged between the first elastic body 5-1 and the second elastic body 5-2. The side wall portion 14 is arranged so as to surround the first elastic body 5-1 in the plane direction. The periphery of the second elastic body 5-2 is not surrounded by the frame body 11.

[0057] As in the present embodiment, the frame body 11 may be arranged so as to surround at least the first elastic body 5-1 in the plane direction. That is, if the swelling in the plane direction of at least the first elastic body 5-1 is restricted, the laminate body 2 can be uniformly pressurized in the plane direction.

[0058] Also, as in the present embodiment, the first elastic body 5-1 and the second elastic body 5-2 may be separated by the frame body 11. As described in the first embodiment, it is preferable that the first elastic body 5-1 and the second elastic body 5-2 are in contact with each other. However, even if the first elastic body 5-1 and the second elastic body 5-2 are separated, pressure is applied from the second elastic body 5-2 to the first elastic body 5-1 via the frame body 11. Therefore, a certain effect can be obtained with respect to uneven absorption and expansion / contraction followability.

[0059] Note that FIG. 9B is a diagram showing a modification of the present embodiment. In this modification, as in the second embodiment, a plurality of laminate bodies 2 are arranged. And the elastic mechanism 5 and the frame body 11 are also arranged between adjacent laminate bodies 2. Even if such a configuration is adopted, a certain effect can be obtained with respect to uneven absorption and expansion / contraction followability.

[0060] (5) Fifth Embodiment Next, the fifth embodiment will be described. Regarding the points where the same configuration as the above-described embodiments can be adopted, detailed description will be omitted.

[0061] FIG. 10A is a schematic view showing the storage battery 1 according to the present embodiment. In the present embodiment, the frame body 11 is integral with at least one of the pair of end plates (3-1 and 3-2). In the example shown in FIG. 10A, the frame body 11 is integral with the end plate 3-1. Specifically, the end plate 3-1 has a flat plate portion 15 and a side wall portion 16. The flat plate portion 15 is disposed on the surface of the second elastic body 5-2. The side wall portion 16 is coupled to the outer peripheral end of the flat plate portion 15 and extends along the stacking direction from the outer peripheral end. The elastic mechanism 5 is surrounded by this side wall portion 16. That is, the swelling in the plane direction in the elastic mechanism 5 is restricted by the side wall portion 16.

[0062] Even if the configuration as in this embodiment is adopted, the same operational effects as in the aforementioned embodiments can be achieved. Further, according to this embodiment, during manufacturing, it becomes easier to align the elastic mechanism 5 and the laminate 2. Also, compared to the example shown in FIG. 1, the thickness of the storage battery 1 can be reduced, and the energy density can be improved.

[0063] FIG. 10B is a diagram showing a modification of this embodiment. In this modification, as in the second embodiment, a plurality of laminates 2 are arranged. And the elastic mechanism 5 is also arranged between adjacent laminates 2. That is, a plurality of elastic mechanisms 5 are arranged. The elastic mechanism 5 arranged on the side closest to the end plate 3-1 among the plurality of elastic mechanisms 5 is surrounded by the side wall portion 16 of the end plate 3-1. Regarding the frame body 11 surrounding the other elastic mechanisms 5, a frame body having the same configuration as the example shown in FIG. 1 is used.

[0064] FIG. 10C is a diagram showing another modification of this embodiment. In this modification, as in the example shown in FIG. 10C, a plurality of laminates 2 are arranged. The elastic mechanism 5 arranged on the side closest to the end plate 3-1 among the plurality of elastic mechanisms 5 is surrounded by the side wall portion 16 of the end plate 3-1. Regarding the frame body 11 surrounding the other elastic mechanisms 5, a frame body having the same configuration as the example shown in FIG. 8A is used. That is, an annular frame body 11 lacking the flat plate portion 13 is used.

[0065] [Examples] Subsequently, the experimental results conducted by the present inventors will be described.

[0066] (Experimental Example 1) A storage battery 1 having the configuration shown in FIG. 1 was prepared as Example 1. On the other hand, as Comparative Example 1, a storage battery using only the first elastic body 5-1 as the elastic mechanism 5 and lacking the frame body 11 was prepared. Also, as Comparative Example 2, a storage battery using only the first elastic body 5-1 as the elastic mechanism 5 and having the frame body 11 was prepared. Then, for each of Example 1, Comparative Example 1, and Comparative Example 2, a 60°C rate test and a cycle test were conducted.

[0067] The results are shown in FIG. 11. Note that FIGS. 11(a) to 11(c) are the results of the 60° C. rate test, and FIGS. 11(d) to 11(f) are the results of the cycle test. FIG. 11(a) shows the result of Comparative Example 1, FIG. 11(b) shows the result of Comparative Example 2, and FIG. 11(c) shows the result of Example 1. Also, FIG. 11(d) shows the result of Comparative Example 1, FIG. 11(e) shows the result of Comparative Example 2, and FIG. 11(f) shows the result of Example 1. As shown in FIG. 11, it was found that the rapid discharge and cycle characteristics were improved by adopting the configuration according to the embodiment of the present invention.

[0068] (Experimental Example 2) As the storage batteries according to Examples 1 to 7, all-solid-state batteries were prepared. As the all-solid-state battery, a battery using metallic lithium as the negative electrode active material was used. FIG. 12 is a table showing the configurations and characteristics of the storage batteries according to Examples 1 to 7. "Configuration" in FIG. 12 shows the lamination order of a pair of end plates, a frame body, a first elastic body, a second elastic body, and a laminate. Examples 1 to 2 are comparative examples, and Examples 3 to 7 are examples. As the first elastic body, in all examples, the stress-strain curve during strain increase was linear, the final strain was 1.2 mm, it had a dense structure, and it was formed of silicon rubber. On the other hand, as the second elastic body, a stress-strain curve that was non-linear, had a foam shape (porous structure), and was formed of fluorine-based rubber was used. The final strain and inflection point of the second elastic body are as shown in FIG. 12.

[0069] For the storage batteries according to Examples 1 to 7, the rapid charge capacity retention rate, the rapid discharge capacity retention rate, and the cycle capacity retention rate were measured. The results are shown in FIG. 12. As shown in FIG. 12, Examples 3 to 7, which are examples, were superior to Comparative Examples 1 and 2 in terms of the rapid charge capacity retention rate, the rapid discharge capacity retention rate, and the cycle capacity retention rate. From this, it was found that the charge-discharge characteristics were improved by this embodiment.

[0070] [Appendix] Below, the typical configurations and their effects of the embodiments of the present invention are summarized as an appendix.

[0071] (Appendix 1) A storage battery comprising: a laminate having an electrolyte layer 7, a positive electrode layer 8, and a negative electrode layer 6; a pair of end plates (3-1 and 3-2) arranged so as to sandwich the laminate 2 in the stacking direction; a pressing mechanism 4 for pressing the end plates; and an elastic mechanism 5 disposed between at least one of the pair of end plates and the laminate. The elastic mechanism includes a first elastic body 5-1 having a stress-strain curve such that the relationship between stress and strain is linear when the strain increases, and a second elastic body 5-2 having a stress-strain curve such that the relationship between stress and strain is non-linear and the elastic modulus increases as the strain increases. The first elastic body is disposed between the second elastic body and the laminate.

[0072] According to the above configuration, a storage battery that achieves both unevenness absorption and expansion / contraction absorption can be obtained.

[0073] (Appendix 2) The storage battery according to Appendix 1, wherein the first elastic body has a stress-strain curve such that the relationship between stress and strain is non-linear and the elastic modulus decreases as the strain decreases when the strain decreases.

[0074] According to the above configuration, when only the first elastic body is used, it becomes difficult for pressure to be applied during the contraction of the laminate 2. By using the second elastic body, it becomes possible to apply a desired pressure to the laminate 2.

[0075] (Appendix 3) The storage battery according to Appendix 1 or 2, wherein the laminate is configured such that its thickness changes with charge and discharge, and the final strain of the second elastic body is greater than the final strain of the first elastic body, and the final strain is the magnitude of the strain of the elastic body when the thickness of the laminate is maximum.

[0076] According to the above configuration, the expansion / contraction followability is further improved.

[0077] (Appendix 4) The storage battery according to any one of Supplementary Notes 1 to 3, wherein the strain at the inflection point in the stress-strain curve of the second elastic body is greater than the final strain of the first elastic body, and the final strain is the magnitude of the strain of the elastic body when the thickness of the laminate is maximum, and the inflection point is the portion where the elastic modulus of the second elastic body changes.

[0078] According to the above configuration, the expansion and contraction followability can be further improved in the vicinity of the restraint pressure (pressing force) during actual use.

[0079] (Supplementary Note 5) The storage battery according to any one of Supplementary Notes 1 to 4, wherein the first elastic body and the second elastic body are in contact with each other.

[0080] According to the above configuration, since the reaction force of the second elastic body is directly applied to the first elastic body, pressure is more likely to be applied to the laminate, and the expansion and contraction followability is further improved.

[0081] (Supplementary Note 6) The storage battery according to any one of Supplementary Notes 1 to 5, further comprising a frame body disposed so as to surround the first elastic body in a plane direction which is a direction perpendicular to the stacking direction, and suppressing the swelling of the first elastic body in the plane direction.

[0082] According to the above configuration, the laminate can be uniformly pressed in the plane direction.

[0083] (Supplementary Note 7) The storage battery according to Supplementary Note 6, wherein the frame body is integral with at least one of a pair of end plates.

[0084] According to the above configuration, it becomes easy to align the elastic body and the laminate. In addition, there is no need to separately provide the frame body, and the thickness of the storage battery can be reduced.

[0085] (Supplementary Note 8) The storage battery according to any one of Supplementary Notes 1 to 7, wherein a plurality of laminates are arranged along the stacking direction, and the elastic mechanism is also arranged between adjacent laminates.

[0086] According to the above configuration, when there are a plurality of laminates, pressure can be uniformly applied to each laminate.

[0087] (Appendix 9) A storage battery according to any one of Appendices 1 to 8, wherein the laminate is arranged such that the positive electrode layer faces the elastic mechanism side.

[0088] According to the above configuration, even if irregularities are present on the surface of the positive electrode layer, pressure can be uniformly applied.

[0089] (Appendix 10) A storage battery according to any one of Appendices 1 to 9, wherein the first elastic body has a dense structure and the second elastic body has a porous structure.

[0090] According to the above configuration, it is easy to obtain the first elastic body and the second elastic body having a desired stress-strain curve.

[0091] (Appendix 11) A storage battery according to any one of Appendices 1 to 10, wherein the first elastic body contains silicone rubber and the second elastic body contains fluorine-based rubber.

[0092] According to the above configuration, it is easy to obtain the first elastic body and the second elastic body having a desired stress-strain curve.

Explanation of Reference Numerals

[0093] 1... Storage battery, 2... Laminate, 3-1 to 3-2... End plates, 4... Pressurizing mechanism, 5... Elastic mechanism, 5-1... First elastic body, 5-2... Second elastic body, 6... Negative electrode layer, 7... Electrolyte layer, 8... Positive electrode layer, 9... Insulating layer, 10... Laminating material, 11... Frame body, 12-1 to 12-n... Cells, 13... Flat plate portion, 14... Side wall portion

Claims

1. A laminate having an electrolyte layer, a positive electrode layer, and a negative electrode layer; A pair of end plates arranged so as to sandwich the laminate in the lamination direction; A pressurizing mechanism for pressurizing the end plates; An elastic mechanism disposed between at least one of the pair of end plates and the laminate; Comprising: The elastic mechanism includes: A first elastic body having a stress-strain curve such that the relationship between stress and strain is linear when the strain increases; A second elastic body having a stress-strain curve in which the relationship between stress and strain is non-linear and the elastic modulus increases as the strain increases; The first elastic body is disposed between the second elastic body and the laminate; A storage battery.

2. The storage battery according to Claim 1, wherein The first elastic body has a stress-strain curve in which the relationship between stress and strain is non-linear and the elastic modulus decreases as the strain decreases when the strain decreases; A storage battery.

3. The storage battery according to Claim 1 or 2, wherein The laminate is configured such that its thickness changes with charge and discharge; The final strain of the second elastic body is greater than the final strain of the first elastic body; The final strain is the magnitude of the strain of the elastic body when the thickness of the laminate is maximum; A storage battery.

4. The storage battery according to Claim 1 or 2, wherein The strain at the inflection point in the stress-strain curve of the second elastic body is greater than the final strain of the first elastic body; The final strain is the magnitude of the strain of the elastic body when the thickness of the laminate is maximum; The inflection point is the portion where the elastic modulus of the second elastic body changes; A storage battery.

5. The storage battery according to Claim 1 or 2, wherein The first elastic body and the second elastic body are in contact with each other; A storage battery.

6. The storage battery according to Claim 1 or 2, further comprising: Furthermore, A frame body disposed so as to surround the first elastic body in a plane direction which is a direction perpendicular to the lamination direction, for suppressing the swelling of the first elastic body in the plane direction; A storage battery.

7. The storage battery according to Claim 6, wherein The frame body is integral with at least one of the pair of end plates; A storage battery.

8. The storage battery according to Claim 1 or 2, wherein A plurality of the laminates are arranged along the lamination direction; The elastic mechanism is also disposed between adjacent laminates; A storage battery.

9. The storage battery according to Claim 1 or 2, wherein The laminate is arranged such that the positive electrode layer faces the elastic mechanism side; A storage battery.

10. The storage battery according to claim 1 or 2, wherein the first elastic body has a dense structure, the second elastic body has a porous structure, a storage battery.

11. The storage battery according to claim 1 or 2, wherein the first elastic body contains silicone rubber, the second elastic body contains fluorine-based rubber, a storage battery.

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