Secondary batteries

Abstract

To provide a new technology that can suppress wrinkles and other issues in the current collector foil that occur during charging and discharging. [Solution] The secondary battery comprises a first current collector foil, a first electrode layer disposed on the first current collector foil, an electrolyte layer disposed on the first electrode layer, a second electrode layer disposed on the electrolyte layer, and a second current collector foil disposed on the second electrode layer. The first electrode layer has an intermittent electrode layer disposed on the first current collector foil and a full-surface electrode layer disposed on the intermittent electrode layer and in contact with the electrolyte layer. In the intermittent electrode layer, the constituent material of the first electrode layer is intermittently arranged so as to be divided into a plurality of intermittent electrode portions that are separated from each other. In the full-surface electrode layer, the constituent material of the first electrode layer is disposed over the entire surface.

Description

Technical Field

[0001] The present invention relates to secondary batteries.

Background Art

[0002] A secondary battery is a battery that can be repeatedly charged and discharged. As a secondary battery, there is known one including an electrolyte layer containing a solid electrolyte, a pair of electrode layers disposed so as to sandwich the electrolyte layer, and a pair of current collector foils disposed on the pair of electrode layers. In such a secondary battery, generally, lithium ions are involved in charging and discharging. That is, during charging and discharging, lithium ions move between the positive electrode layer and the negative electrode layer through the electrolyte layer. In each electrode layer, an electrochemical reaction via lithium ions proceeds.

[0003] In the secondary battery as described above, the electrode layer may expand and contract with charging and discharging. Due to the expansion and contraction of the electrode layer, the current collector foil may break. Alternatively, wrinkles may occur in the current collector foil.

[0004] In relation to the above, an invention aimed at providing a secondary battery capable of preventing damage to the current collector foil is described in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2024-147864). Patent Document 1 discloses "a secondary battery using a solid electrolyte including a power generation body in which a plurality of single cells are stacked, a laminated exterior body whose periphery is sealed and which houses the power generation body inside, and a current collector tab disposed at a sealing portion of the laminated exterior body and partially protruding from the laminated exterior body, wherein each current collector of the single cell is connected to the current collector tab by a current collector foil, and an elastic member is disposed between a joint portion of the current collector foil and the current collector tab and the power generation body and at a position contacting the current collector foil".

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] It would be preferable if a new technology could be provided that can suppress wrinkles and other defects in the current collector foil. Therefore, the object of the present invention is to provide a new technology that can suppress wrinkles and other defects in the current collector foil that occur during charging and discharging. [Means for solving the problem]

[0007] In one embodiment, the secondary battery according to the present invention comprises a first current collector foil, a first electrode layer disposed on the first current collector foil, an electrolyte layer disposed on the first electrode layer and containing a solid electrolyte, a second electrode layer disposed on the electrolyte layer, and a second current collector foil disposed on the second electrode layer. The first electrode layer has an intermittent electrode layer disposed on the first current collector foil and a full-surface electrode layer disposed on the intermittent layer and in contact with the electrolyte layer. In the intermittent electrode layer, the constituent material of the first electrode layer is intermittently arranged so as to be divided into a plurality of intermittent electrode portions that are separated from each other. In the full-surface electrode layer, the constituent material of the first electrode layer is arranged over the entire surface. [Effects of the Invention]

[0008] The present invention provides a new technology that can suppress wrinkles and other issues in the current collector foil that occur during charging and discharging. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic cross-sectional view showing a secondary battery according to the first embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view showing a secondary battery according to a reference example. [Figure 3] Figure 3 is a schematic cross-sectional view showing the charging and discharging of a secondary battery according to the first embodiment. [Figure 4] Figure 4 is a plan view showing an example of the configuration of the intermittent electrode layer. [Figure 5]Figure 5 is a schematic cross-sectional view showing a secondary battery according to the second embodiment. [Figure 6] Figure 6 is a schematic cross-sectional view showing a secondary battery according to the third embodiment. [Figure 7] Figure 7 is a schematic cross-sectional view showing a secondary battery according to the fourth embodiment. [Figure 8] Figure 8 is a schematic cross-sectional view showing a secondary battery according to the fifth embodiment. [Figure 9] Figure 9 is a schematic cross-sectional view showing a secondary battery according to the sixth embodiment. [Figure 10] Figure 10 is a schematic cross-sectional view showing a secondary battery according to the seventh embodiment. [Figure 11] Figure 11 is a schematic cross-sectional view showing a secondary battery according to the eighth embodiment. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings.

[0011] (1) First Embodiment Figure 1 is a schematic cross-sectional view showing a secondary battery 1 according to the first embodiment. The secondary battery 1 has a first current collector foil 2, a first electrode layer 3, an electrolyte layer 4, a second electrode layer 5, and a second current collector foil 6. These are stacked in this order. That is, the first electrode layer 3 is placed on the first current collector foil 2, the electrolyte layer 4 is placed on the first electrode layer 3, the second electrode layer 5 is placed on the electrolyte layer 4, and the second current collector foil 6 is placed on the second electrode layer 5.

[0012] The electrolyte layer 4 is the layer through which lithium ions are conducted during charging and discharging. The electrolyte layer 4 contains a solid electrolyte. The amount of solid electrolyte included is such that the electrolyte layer 4 as a whole is solid. In other words, the electrolyte layer 4 has a fixed shape, not an amorphous one. Examples of solid electrolytes include sulfide-based electrolytes.

[0013] One of the first electrode layer 3 and the second electrode layer 5 sandwiching the electrolyte layer 4 is a positive electrode layer, and the other is a negative electrode layer. Each electrode layer contains an active material.

[0014] The positive electrode layer is configured to release lithium ions during charging and take in lithium ions during discharging. The positive electrode layer is formed of a material containing, for example, a resin binder, a positive electrode active material, a conductive assistant, and a solid electrolyte.

[0015] The negative electrode layer is configured to take in lithium ions during charging and release lithium ions during discharging. The negative electrode layer is formed of a material containing, for example, a resin binder and a negative electrode active material. Examples of the negative electrode active material include a carbon-based active material, a silicon-based active material, and a metal-based active material.

[0016] Here, in the present embodiment, the configuration of the first electrode layer 3 is devised. Specifically, the first electrode layer 3 has an intermittent electrode layer 7 and a full-surface electrode layer 8.

[0017] The intermittent electrode layer 7 is disposed in contact with the first current collector foil 2. In the intermittent electrode layer 7, the constituent material of the first electrode layer 3 is intermittently disposed so as to be divided into a plurality of intermittent electrode portions 9 that are separated from each other.

[0018] The full-surface electrode layer 8 is disposed on the intermittent electrode layer 7. The full-surface electrode layer 8 is in contact with the electrolyte layer 4. In the full-surface electrode layer 8, as the name implies, the constituent material of the first electrode layer 3 is disposed over the entire surface. The entire surface here refers to the entire surface of the charge / discharge region in the secondary battery 1. The charge / discharge region is a region where lithium ions conduct during charge / discharge, and is a region where the first electrode layer 3, the electrolyte layer 4, and the second electrode layer 5 overlap.

[0019] The above is the schematic configuration of the secondary battery 1 according to the present embodiment.

[0020] In this embodiment, during charging and discharging, lithium ions are conducted between the first electrode layer 3 and the second electrode layer 5. Electrochemical reactions mediated by lithium ions proceed within each electrode layer. During this process, each electrode layer expands and contracts.

[0021] Here, if the intermittent electrode layer 7 is not provided in the first electrode layer 3, that is, if the first electrode layer 3 consists only of the full-surface electrode layer 8, the expansion and contraction of the first electrode layer 3 may pull on the first current collector foil 2, potentially causing wrinkles or other damage to the first current collector foil 2.

[0022] Furthermore, even if the first electrode layer 3 is not provided with a full-surface electrode layer 8, that is, if the first electrode layer 3 consists only of an intermittent electrode layer 7, wrinkles may still occur. For details, please refer to Figure 2. Figure 2 is a schematic cross-sectional view showing a secondary battery according to a reference example. In this reference example, the entire first electrode layer 3 is an intermittent electrode layer 7, and there is no full-surface electrode layer 8. In this reference example, during charging and discharging, electrons or ions may be locally conducted in one of the multiple intermittent electrode portions 9. In other words, reactions related to charging and discharging may proceed locally. As a result, a certain intermittent electrode portion 9 may expand and contract locally, which may cause localized wrinkles in the first current collector foil 2.

[0023] On the other hand, Figure 3 is a schematic cross-sectional view showing the charging and discharging of the secondary battery 1 according to this embodiment. In this embodiment, the first current collector foil 2 and the first electrode layer 3 are in contact at the intermittent electrode layer 7. Compared to the case where the entire surface of the first electrode layer 3 is in contact with the first current collector foil 2, the contact area between the first electrode layer 3 and the first current collector foil 2 is smaller. The first current collector foil 2 is less affected by the expansion and contraction of the first electrode layer 3, and wrinkles and the like are less likely to occur.

[0024] In addition, the first electrode layer 3 is in contact with the electrolyte layer 4 across the entire electrode layer 8. Therefore, during charging and discharging, ions and electrons move throughout the entire charging and discharging region. That is, electrons and ions can move even in the gaps between adjacent intermittent electrode portions 9. As a result, localized charging and discharging reactions can be prevented. That is, localized expansion and contraction of the first electrode layer 3 can be prevented. As a result, the occurrence of localized wrinkles and other defects in the first current collector foil 2 is also suppressed.

[0025] The above is an overview of this embodiment.

[0026] The shape of each intermittent electrode portion 9 in the intermittent electrode layer 7 is not particularly limited. However, it is preferable that the multiple intermittent electrode portions 9 are arranged in a specific direction and at specific intervals. Figure 4 is a plan view showing an example of the configuration of the intermittent electrode layer 7. In the example shown in Figure 4, each intermittent electrode portion 9 has a shape that extends in one direction. The multiple intermittent electrode portions 9 are arranged in parallel at regular intervals.

[0027] However, the layout of the multiple intermittent electrode portions 9 is not limited to the layout shown in Figure 4. For example, each intermittent electrode portion 9 may be a regular hexagon, and multiple intermittent electrode portions 9 may be arranged in a honeycomb pattern.

[0028] Furthermore, in the example shown in Figure 1, the second electrode layer 5 does not have an intermittent configuration, unlike the first electrode layer 3. However, the second electrode layer 5 may also have a configuration similar to that of the first electrode layer 3. That is, the second electrode layer 5 may also have an intermittent electrode layer 7 in contact with the second current collector foil 6 and a full-surface electrode layer 8 in contact with the electrolyte layer 4.

[0029] (2) Second embodiment Next, a second embodiment will be described. Figure 5 is a schematic cross-sectional view showing the secondary battery 1 according to this embodiment. The secondary battery 1 according to this embodiment is a monopolar secondary battery 1. A monopolar secondary battery is a secondary battery having a configuration in which electrode layers having the same polarity are formed on both sides of a single current collector foil. In this specification, "polarity" is used to indicate whether it is a positive electrode or a negative electrode.

[0030] Specifically, as shown in Figure 5, in this embodiment, the secondary battery 1 has a first unit and a second unit. Each unit has a laminated structure consisting of a first electrode layer 3, an electrolyte layer 4, and a second electrode layer 5. The first unit and the second unit are arranged so as to sandwich the first current collector foil 2. That is, the first electrode layer 3, the electrolyte layer 4, the second electrode layer 5, and the second current collector foil 6 are laminated in this order on both sides of the first current collector foil 2. In each unit, one of the first electrode layer 3 and the second electrode layer 5 is the positive electrode layer, and the other is the negative electrode layer.

[0031] The polarity of the first electrode layer 3 is the same on both sides of the first current collector foil 2. That is, the first electrode layer 3 of the first unit and the first electrode layer 3 of the second unit have the same polarity. In the example shown in Figure 5, both the first electrode layer 3 of the first unit and the first electrode layer 3 of the second unit are negative electrode layers. Also, the second electrode layer 5 in each unit is a positive electrode layer. However, each first electrode layer 3 may be a positive electrode layer and each second electrode layer 5 may be a negative electrode layer.

[0032] In this embodiment, when viewed along the lamination direction, the positions of the ends of each intermittent electrode portion 9 differ between the two sides of the first current collector foil 2. That is, the position of the end of each intermittent electrode portion 9 in the first unit (see position B in the figure) is different from the position of the end of each intermittent electrode portion 9 in the second unit (see position A in the figure).

[0033] With the configuration described above, the force applied from the first electrode layer 3 to the first current collector foil 2 during expansion and contraction is canceled out between the two surfaces of the first current collector foil 2. Specifically, please refer to the arrows in Figure 5. As shown in Figure 5, at the position where the first electrode layer 3 in the first unit expands in the planar direction (perpendicular to the lamination direction), the first electrode layer 3 in the second unit expands in the opposite direction. Therefore, the forces applied to the first current collector foil 2 are canceled out. This more reliably prevents the occurrence of wrinkles and the like.

[0034] (3) Third Embodiment Next, a third embodiment will be described. Figure 6 is a schematic cross-sectional view showing the secondary battery 1 according to this embodiment. The secondary battery 1 according to this embodiment is a bipolar secondary battery 1. A bipolar secondary battery is a secondary battery having a configuration in which electrode layers having opposite polarities are formed on both sides of a single current collector foil.

[0035] Specifically, similar to the second embodiment, this embodiment also includes a secondary battery 1 comprising a first unit and a second unit. Each unit has a laminated structure consisting of a first electrode layer 3, an electrolyte layer 4, and a second electrode layer 5. The first unit and the second unit are arranged so as to sandwich the first current collector foil 2. In each unit, the first electrode layer 3, electrolyte layer 4, second electrode layer 5, and second current collector foil 6 are laminated in this order from the side of the first current collector foil 2. In each unit, the first electrode layer 3 has an intermittent electrode layer 7 and a full-surface electrode layer 8.

[0036] However, unlike the second embodiment, in this embodiment, the polarity of the first electrode layer 3 is reversed on both sides of the first current collector foil 2. That is, the first electrode layer 3 located on one side of the first current collector foil 2 is the positive electrode layer, while the first electrode layer 3 located on the other side of the first current collector foil 2 is the negative electrode layer. In the example shown in Figure 6, the first electrode layer 3 of the first unit is the positive electrode layer. On the other hand, the first electrode layer 3 of the second unit is the negative electrode layer.

[0037] In this embodiment, when viewed along the stacking direction, the outer peripheral edge of each intermittent electrode portion 9 in the positive electrode layer (see position B in Figure 6) is aligned with the outer peripheral edge of each intermittent electrode portion 9 in the negative electrode layer (see position A in Figure 6). In other words, the positions of the ends of the intermittent electrode portions 9 are aligned on both sides of the first current collector foil 2.

[0038] In this embodiment, as in the second embodiment, the forces applied from the first electrode layer 3 to the first current collector foil 2 during charging and discharging are canceled out. Specifically, during charging and discharging of the secondary battery 1, when the negative electrode layer expands, the positive electrode layer contracts. Conversely, when the negative electrode layer contracts, the positive electrode layer expands. For example, during charging, the negative electrode layer expands and the positive electrode layer contracts. During discharging, the negative electrode layer contracts and the positive electrode layer expands. That is, as indicated by the arrows in Figure 6, when one first electrode layer 3 expands, the other first electrode layer 3 contracts, so the forces applied to the first current collector foil 2 are canceled out. As a result, the occurrence of wrinkles is suppressed.

[0039] In the example shown in Figure 6, each unit has both a full-surface electrode layer and an intermittent electrode layer in both the positive electrode layer and the negative electrode layer. In other words, in each unit, not only the first electrode layer 3 but also the second electrode layer 5 has both a full-surface electrode layer and an intermittent electrode layer.

[0040] (4) Fourth embodiment Next, a fourth embodiment will be described. Figure 7 is a schematic cross-sectional view showing the secondary battery 1 according to this embodiment. This embodiment can also be said to be a modified version of the third embodiment. Therefore, only the parts that differ from the third embodiment will be described, and detailed explanations of the parts that can be adopted in the same configuration will be omitted.

[0041] As shown in Figure 7, in this embodiment, the position of the outer edge of the intermittent electrode portion 9 differs between the positive electrode layer and the negative electrode layer. That is, the position of the end of each intermittent electrode portion 9 included in the first electrode layer 3 differs between the two sides of the first current collector foil 2.

[0042] Specifically, when viewed along the stacking direction, the outer edge of each intermittent electrode portion 9 in the negative electrode layer (see position A in Figure 7) is located inward from the outer edge of each intermittent electrode portion 9 in the positive electrode layer (see position B in Figure 7). In other words, when viewed along the stacking direction, the intermittent electrode portion 9 in the positive electrode layer is wider than the intermittent electrode portion 9 in the negative electrode layer.

[0043] According to this embodiment, breakage and wrinkling of the first current collector foil 2 are more reliably prevented. In secondary batteries 1 containing a solid electrolyte, the amount of expansion and contraction during charging and discharging is often greater in the negative electrode layer than in the positive electrode layer. According to this embodiment, the negative electrode layer, which is more prone to expansion and contraction, is smaller than the positive electrode layer, which is less prone to expansion and contraction. Therefore, the force applied to the first current collector foil 2 due to the expansion and contraction of the positive electrode layer and the force applied to the first current collector foil 2 due to the expansion and contraction of the negative electrode layer are more easily balanced. As a result, breakage and wrinkling are more reliably prevented.

[0044] (4) Fifth embodiment Next, a fifth embodiment will be described. In this embodiment, the spacing between the multiple intermittent electrode portions 9 is carefully designed. Detailed explanations will be omitted regarding aspects where the same configuration as in the previously described embodiments can be adopted.

[0045] Figure 8 is a schematic cross-sectional view showing the secondary battery 1 according to this embodiment. Figure 8(a) shows the initial configuration (immediately after manufacturing), Figure 8(b) shows the configuration when fully charged, and Figure 8(c) shows the configuration when completely discharged.

[0046] As shown in Figure 8, in this embodiment, the multiple intermittent electrode portions 9 in the first electrode layer 3 are spaced apart so that they do not come into contact with each other, both when fully charged (Figure 8(b)) and when completely discharged (Figure 8(c)). The secondary battery 1 shown in Figure 8 is of the bipolar type, and the second electrode layer 5 also has a full electrode layer and an intermittent electrode layer. The multiple intermittent electrode portions in the second electrode layer 5 are also spaced apart so that they do not come into contact with each other, both when fully charged and completely discharged.

[0047] As described above, the first electrode layer 3 expands and contracts during charging and discharging. As a result, during expansion, the distance between adjacent intermittent electrode portions 9 decreases. If the gap disappears during expansion, wrinkles and other defects are more likely to occur in the first current collector foil 2. In contrast, according to this embodiment, multiple intermittent electrode portions 9 are spaced apart so that they do not come into contact with each other, whether fully charged or completely discharged. That is, regardless of the charging and discharging state, adjacent intermittent electrode portions 9 remain separated. Therefore, the occurrence of breakage and wrinkles is more reliably suppressed.

[0048] Figure 8 shows the configuration when the secondary battery 1 is bipolar. However, the secondary battery 1 in this embodiment does not necessarily have to be bipolar; it may be monopolar.

[0049] (5) Sixth Embodiment Next, a sixth embodiment will be described. Figure 9 is a schematic cross-sectional view of the secondary battery 1 according to this embodiment. Detailed explanations will be omitted for aspects that can be adopted in the same configuration as the embodiments described above.

[0050] As shown in Figure 9, in this embodiment, an elastic body 10 is provided in the intermittent electrode layer 7. The elastic body 10 is positioned in the gap between adjacent intermittent electrode portions 9.

[0051] According to this embodiment, since the elastic body 10 is provided, the expansion of the first electrode layer 3 is suppressed. As a result, breakage and wrinkling in the first current collector foil 2 are more reliably suppressed.

[0052] (6) Seventh Embodiment Next, a seventh embodiment will be described. Figure 10 is a schematic cross-sectional view of the secondary battery 1 according to this embodiment. Detailed explanations will be omitted for aspects that can be adopted in the same way as in the embodiments described above.

[0053] In this embodiment, the intermittent electrode layer 7 and the full-surface electrode layer 8 are each formed from a material containing the active material 11. Here, the density of the active material 11 in the full-surface electrode layer 8 is greater than the density of the active material in the intermittent electrode layer 7. That is, the density of the active material 11 in the constituent material of the full-surface electrode layer 8 is greater than the density of the active material 11 in the constituent material of the intermittent electrode layer 7.

[0054] In the electrode layers of secondary batteries, generally, the higher the density of the active material, the greater the expansion and contraction during charging and discharging. In this embodiment, since the density of the active material in the intermittent electrode layer 7 is low, the intermittent electrode layer 7 is less likely to expand and contract. Because the intermittent electrode layer 7 in contact with the first current collector foil 2 is less likely to expand and contract, the first current collector foil 2 is less affected by the expansion and contraction of the first electrode layer 3. Wrinkles and the like are suppressed more reliably.

[0055] (7) Eighth embodiment Next, an eighth embodiment will be described. Figure 11 is a schematic cross-sectional view of the secondary battery 1 according to this embodiment. Detailed explanations will be omitted for aspects where the same configuration as in the previously described embodiments can be adopted.

[0056] In this embodiment, the intermittent electrode layer 7 and the full-surface electrode layer 8 are each formed from a material containing an active material and a binder 12. Here, the density of the binder 12 in the full-surface electrode layer 8 is smaller than the density of the binder 12 in the intermittent electrode layer 7. That is, the density of the binder 12 in the constituent material of the full-surface electrode layer 8 is smaller than the density of the binder 12 in the constituent material of the intermittent electrode layer 7.

[0057] In the electrode layers of a secondary battery, generally, the higher the density of the binder 12, the smaller the amount of expansion and contraction associated with charging and discharging. In this embodiment, since the density of the binder 12 in the intermittent electrode layer 7 is high, the intermittent electrode layer 7 is less likely to expand and contract. Because the intermittent electrode layer 7 in contact with the first current collector foil 2 is less likely to expand and contract, wrinkles in the first current collector foil 2 are more reliably suppressed.

[0058] [Note] The present invention has been described above with reference to embodiments and their modifications. A representative configuration and its effects included in the present invention are summarized below as an appendix.

[0059] (Note 1) A secondary battery comprising: a first current collector foil 2; a first electrode layer 3 disposed on the first current collector foil; an electrolyte layer 4 disposed on the first electrode layer and containing a solid electrolyte; a second electrode layer 5 disposed on the electrolyte layer; and a second current collector foil 6 disposed on the second electrode layer, wherein the first electrode layer 3 has an intermittent electrode layer 7 disposed on the first current collector foil and a full-surface electrode layer 8 disposed on the intermittent electrode layer and in contact with the electrolyte layer 4, wherein in the intermittent electrode layer 7, the constituent material of the first electrode layer is intermittently arranged so as to be divided into a plurality of intermittent electrode portions 9 that are separated from each other, and in the full-surface electrode layer 8, the constituent material of the first electrode layer is disposed over the entire surface.

[0060] According to the above configuration, the first electrode layer 3 is in contact with the first current collector foil 2 in the intermittent electrode layer 7, so the first current collector foil 2 is less affected by the expansion and contraction of the first electrode layer 3. Therefore, the occurrence of wrinkles and other defects in the first current collector foil 2 is suppressed. In addition, since the first electrode layer 3 is in full contact with the electrolyte layer 4 in the full electrode layer 8, electrons and ions move across the entire surface of the first electrode layer 3 during charging and discharging. This suppresses localized progress of the charge-discharge reaction in certain areas, and prevents localized expansion and contraction of the first electrode layer 3. Consequently, the occurrence of localized wrinkles in the first current collector foil 2 is suppressed.

[0061] (Note 2) A secondary battery as described in Appendix 1, wherein the battery is of the monopolar type, the first electrode layer 3 is provided on both sides of the first current collector foil 2, the polarity of the first electrode layer 3 is the same on both sides of the first current collector foil 2, and when viewed along the lamination direction, the positions of the ends of each of the multiple intermittent electrode portions 9 are different on both sides of the first current collector foil 2.

[0062] According to the above configuration, when the first electrode layer 3 expands and contracts, the force applied from the first electrode layer 3 to the first current collector foil 2 is in opposite directions on both sides of the first current collector foil 2. As a result, the forces applied to the first current collector foil 2 cancel each other out, and the occurrence of wrinkles and the like is more reliably suppressed.

[0063] (Note 3) A secondary battery as described in Appendix 2, wherein the first electrode layer 3 is the negative electrode layer.

[0064] According to the above configuration, the expansion and contraction of the negative electrode layer prevents wrinkles and other damage from occurring in the current collector foil.

[0065] (Note 4) A secondary battery as described in Appendix 2, wherein the first electrode layer 3 is the positive electrode layer.

[0066] According to the above configuration, the expansion and contraction of the positive electrode layer prevents wrinkles and other defects from occurring in the current collector foil.

[0067] (Note 5) A secondary battery as described in Appendix 1, which is of the bipolar type, wherein the first electrode layer 3 is provided on both sides of the first current collector foil 2, the first electrode layer 3 located on one side of the first current collector foil 2 is the positive electrode layer, the first electrode layer 3 located on the other side of the first current collector foil 2 is the negative electrode layer, and when viewed along the stacking direction, the positions of the ends of each of the multiple intermittent electrode portions 9 are aligned between the two sides of the first current collector foil 2.

[0068] According to the above configuration, when the first electrode layer 3 expands and contracts between both sides of the first current collector foil 2, the direction of the force applied from the first electrode layer 3 to the first current collector foil 2 is reversed. As a result, the forces applied to the first current collector foil 2 cancel each other out, and the occurrence of wrinkles and the like is more reliably suppressed.

[0069] (Note 6) A secondary battery as described in Appendix 1, which is of the bipolar type, wherein the first electrode layer 3 is provided on both sides of the first current collector foil 2, the first electrode layer 3 located on one side of the first current collector foil 2 is the positive electrode layer, the first electrode layer 3 located on the other side of the first current collector foil 2 is the negative electrode layer, and when viewed along the stacking direction, the outer peripheral edge of each intermittent electrode portion 9 in the negative electrode layer is located inward from the outer peripheral edge of each intermittent electrode portion 9 in the positive electrode layer.

[0070] In the above configuration, when the first electrode layer 3 expands and contracts between the two sides of the first current collector foil 2, the direction of the force applied from the first electrode layer 3 to the first current collector foil 2 is reversed. Therefore, the forces applied to the first current collector foil 2 cancel each other out. Also, in the above configuration, the positive electrode layer is wider than the negative electrode layer. Generally, the expansion and contraction of the negative electrode layer is greater than that of the positive electrode layer. Therefore, the forces applied to the first current collector foil 2 are more reliably canceled out, and the occurrence of wrinkles and the like is more reliably suppressed.

[0071] (Note 7) A secondary battery as described in any of the appendices 1 to 6, wherein the multiple intermittent electrode portions 9 are spaced apart so that they do not come into contact with each other, neither when fully charged nor when completely discharged.

[0072] With this configuration, in the intermittent electrode layer 7, the constituent material of the first electrode layer is arranged intermittently regardless of the charge / discharge state. Therefore, the occurrence of wrinkles and other defects is more reliably suppressed.

[0073] (Note 8) A secondary battery as described in any of Appendix 1 to 7, wherein the intermittent electrode layer 7 further includes an elastic body 10 disposed in the gaps between a plurality of intermittent electrode portions 9. Secondary battery.

[0074] With this configuration, the expansion and contraction of each intermittent electrode portion 9 in the intermittent electrode layer 7 is suppressed by the elastic body 10. As a result, the occurrence of wrinkles and other defects in the first current collector foil 2 is more reliably suppressed.

[0075] (Note 9) A secondary battery as described in any of the appendices 1 to 8, wherein the full electrode layer 8 and the intermittent electrode layer 7 are each formed of a material containing an active material 11, and the density of the active material 11 in the full electrode layer 8 is greater than the density of the active material 11 in the intermittent electrode layer 7.

[0076] With this configuration, the intermittent electrode layer 7 is less prone to expansion and contraction because the density of the active material 11 is low. Since the intermittent electrode layer 7 in contact with the first electrode layer 3 is less prone to expansion and contraction, the occurrence of wrinkles and other defects in the first current collector foil 2 is more reliably suppressed.

[0077] (Note 10) A secondary battery as described in any of the appendices 1 to 10, wherein the full electrode layer 8 and the intermittent electrode layer 7 are each formed of a material containing a binder, and the density of the binder 12 in the full electrode layer 8 is less than the density of the binder 12 in the intermittent electrode layer 7.

[0078] With this configuration, the intermittent electrode layer 7 is less prone to expansion and contraction because of the high density of the binder 12. Since the intermittent electrode layer 7 in contact with the first electrode layer 3 is less prone to expansion and contraction, the occurrence of wrinkles and other defects in the first current collector foil 2 is more reliably suppressed. [Explanation of Symbols]

[0079] 1...Secondary battery, 2...First current collector foil, 3...First electrode layer, 4...Electrolyte layer, 5...Second electrode layer, 6...Second current collector foil, 7...Intermittent electrode layer, 8...Full electrode layer, 9...Intermittent electrode portion, 10...Elastic body, 11...Active material, 12...Binder

Claims

1. The first current collector foil and A first electrode layer is disposed on the first current collector foil, An electrolyte layer, which is disposed on the first electrode layer and contains a solid electrolyte, A second electrode layer is disposed on the electrolyte layer, A second current collector foil is disposed on the second electrode layer, Equipped with, The first electrode layer is An intermittent electrode layer is disposed on the first current collector foil, It has a full-surface electrode layer that is disposed on the intermittent electrode layer and in contact with the electrolyte layer, In the intermittent electrode layer, the constituent material of the first electrode layer is intermittently arranged so as to be divided into a plurality of intermittent electrode portions that are separated from each other. In the aforementioned full-surface electrode layer, the constituent material of the first electrode layer is arranged over the entire surface. Secondary battery.

2. A secondary battery according to claim 1, It is a monopolar type, The first electrode layer is provided on both sides of the first current collector foil. The polarity of the first electrode layer is the same on both sides of the first current collector foil. When viewed along the stacking direction, the positions of the ends of each of the multiple intermittent electrode portions differ between the two sides of the first current collector foil. Secondary battery.

3. A secondary battery according to claim 2, The first electrode layer is the negative electrode layer. Secondary battery.

4. A secondary battery according to claim 2, The aforementioned first electrode layer is a positive electrode layer. Secondary battery.

5. A secondary battery according to claim 1, It is bipolar, The first electrode layer is provided on both sides of the first current collector foil. The first electrode layer, which is disposed on one surface of the first current collector foil, is a positive electrode layer. The first electrode layer, disposed on the other surface of the first current collector foil, is a negative electrode layer. When viewed along the stacking direction, the positions of the ends of each of the multiple intermittent electrode portions are aligned between the two surfaces of the first current collector foil. Secondary battery.

6. A secondary battery according to claim 1, It is bipolar, The first electrode layer is provided on both sides of the first current collector foil. The first electrode layer, which is disposed on one side of the first current collector foil, is a positive electrode layer. The first electrode layer, which is disposed on the other side of the first current collector foil, is a negative electrode layer. When viewed along the stacking direction, the outer peripheral edge of each intermittent electrode portion in the negative electrode layer is located inward from the outer peripheral edge of each intermittent electrode portion in the positive electrode layer. Secondary battery.

7. A secondary battery according to claim 1 or 2, The aforementioned multiple intermittent electrode portions are spaced apart so that they do not come into contact with each other, neither when fully charged nor fully discharged. Secondary battery.

8. A secondary battery according to claim 1 or 2, The intermittent electrode layer further includes elastic bodies disposed in the gaps between the multiple intermittent electrode portions. Secondary battery.

9. A secondary battery according to claim 1 or 2, The full-surface electrode layer and the intermittent electrode layer are each formed from a material containing an active material. The density of the active material in the full-surface electrode layer is greater than the density of the active material in the intermittent electrode layer. Secondary battery.

10. A secondary battery according to claim 1 or 2, The full-surface electrode layer and the intermittent electrode layer are each formed from a material containing a binder. The density of the binder in the full-surface electrode layer is less than the density of the binder in the intermittent electrode layer. Secondary battery.

Images