Secondary batteries, battery control units, and electronic devices

Abstract

To provide a lithium ion secondary battery using a lithium-containing composite phosphate as a positive electrode active material, a positive electrode active material with a high lithium ion diffusion rate, and a lithium ion secondary battery with high output.SOLUTION: A positive electrode active material for a lithium-ion secondary battery includes a plate-like first structure, and a plate-like second structure, and a prismatic third structure is provided between the first structure and the second structure, and a gap is provided between the first structure and the second structure.SELECTED DRAWING: Figure 33

Description

[Technical Field]

[0001] This invention relates to lithium-containing composite phosphates. Furthermore, it relates to lithium-containing oxides as active materials. This relates to a lithium-ion secondary battery having electrodes for use. It also relates to a battery control unit, and Regarding electronic equipment. [Background technology]

[0002] In recent years, the development of energy storage devices such as lithium-ion secondary batteries has been progressing.

[0003] As an example of the above energy storage device, LiFePO4 (lithium iron phosphate), which is a composite oxide, An example is an energy storage device having electrodes made of an active material. It has electrodes made of LiFePO4. The energy storage device has high thermal stability and good cycle characteristics.

[0004] One method for producing complex oxides such as LiFePO4 is the hydrothermal method (for example) (Patent Document 1). A hydrothermal method is a method of compound synthesis or crystal growth carried out in the presence of hot water. That is the case.

[0005] By using the hydrothermal method, even materials that are difficult to dissolve in water at room temperature and pressure can be dissolved. Therefore, it is possible to synthesize substances or grow crystals that cannot be obtained by production methods at room temperature and atmospheric pressure. This can be done. Furthermore, by using the hydrothermal method, single crystals of the target material can be easily obtained. It is also possible to synthesize these fine particles.

[0006] In the hydrothermal method, for example, a solution containing the raw materials is placed in a pressure vessel and treated by pressurization and heating. The solution, which has been subsequently treated with pressure and heat, is then filtered to produce the desired compound. It is possible. [Prior art documents]

Patent Document

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] Among various applications of lithium-ion secondary batteries, in-vehicle secondary batteries for HEV, EV, PHEV, etc., and stationary secondary batteries have high requirements for high power output. To enable high power output of lithium-ion secondary batteries, it is required that the electrode reaction rate and lithium diffusion rate are high. If lithium diffusion can be accelerated in composite oxides such as LiFePO4 used as the positive electrode active material, the output of the lithium-ion secondary battery can be increased.

[0009] In view of the above, one aspect of the present invention aims to provide a composite oxide such as LiFePO4 with a high lithium diffusion rate. Another aspect of the present invention aims to provide a positive electrode active material with a high lithium diffusion rate. Also, in one aspect of the present invention, it is an object to provide a lithium-ion secondary battery with high output. Further, in one aspect of the present invention, it is an object to provide a novel battery.

[0010] Note that the description of these problems does not prevent the existence of other problems. It should be noted that one aspect of the present invention does not necessarily need to solve all of these problems. Other problems will become apparent from the descriptions in the specification, drawings, claims, etc., and it is possible to extract these other problems from the descriptions in the specification, drawings, claims, etc. ​​​​​​​​​​​ [Means for solving the problem]

[0011] One aspect of the invention disclosed herein comprises a plate-shaped first structure and a plate-shaped second structure and, having a first structure, a second structure, and between them, a third structure, the first structure A lithium-ion secondary battery characterized by having a gap between the fabricated body and the second structure. This is a positive electrode active material for ponds.

[0012] Furthermore, in one embodiment of the present invention, the external shape of the first structure comprises a first surface, a second surface, and It has other faces, the first face is larger in area than the other faces, and the second face is larger than the other faces. This is a positive electrode active material for lithium-ion secondary batteries, characterized by its large surface area.

[0013] Furthermore, in one embodiment of the present invention, the first surface and the second surface do not have a common edge. This is a positive electrode active material for lithium-ion secondary batteries, which is a key feature of this product.

[0014] Furthermore, in one embodiment of the present invention, the first surface is generally n-sided (where n is a natural number greater than or equal to 5). ), characterized in that at least one of the interior angles of the n-sided polygon is 100° or less. This is a positive electrode active material for muon secondary batteries.

[0015] Furthermore, in one embodiment of the present invention, the third structure is generally prismatic in shape, and is connected to the first structure. A lithium iodine characterized by having one or more third structures between two structures. It is a positive electrode active material for secondary batteries.

[0016] Furthermore, in one embodiment of the present invention, the first structure, the second structure, and the third structure are, It contains lithium (Li), metal, phosphorus (P), and oxygen (O), and the metal is iron (Fe), ma One of the following: Mn, Cobalt (Co), Nickel (Ni) This is a positive electrode active material for lithium-ion secondary batteries, characterized by having multiple components.

[0017] Furthermore, in one embodiment of the present invention, the first structure, the second structure, and the third structure are, It is characterized by containing thium (Li), iron (Fe), phosphorus (P), and oxygen (O). This is a positive electrode active material for lithium-ion secondary batteries.

[0018] Furthermore, in one embodiment of the present invention, the first structure, the second structure, and the third structure are, This is a positive electrode active material for lithium-ion secondary batteries, characterized by having lithium iron oxide. .

[0019] Furthermore, in one embodiment of the present invention, the first structure, the second structure, and the third structure are L This is a positive electrode active material for lithium-ion secondary batteries, characterized by having iFePO4.

[0020] Furthermore, a secondary electrode having a positive electrode containing a positive electrode active material according to one aspect of the present invention, a negative electrode, and an electrolyte. A battery is also one aspect of the present invention.

[0021] Furthermore, a battery control unit having a secondary battery and a control circuit according to one aspect of the present invention is also This is one aspect of the present invention.

[0022] Furthermore, an electronic device having a secondary battery and a power switch according to one aspect of the present invention is also a part of the present invention. This is one aspect of the Ming Dynasty.

[0023] Furthermore, an electronic device having a secondary battery and a display device according to one aspect of the present invention is also part of the present invention. This is one aspect of the situation.

[0024] Furthermore, the present invention includes a secondary battery according to one aspect of the present invention and input / output terminals, the input / output terminals being wireless communication Electronic devices that have the function of making communications are also one aspect of the present invention. [Effects of the Invention]

[0025] This invention provides a positive electrode active material with a high lithium diffusion rate. This can provide composite oxides such as LiFePO4 with a high lithium diffusion rate. Furthermore, in one aspect of the present invention, it is possible to provide a lithium-ion secondary battery with high output. Yes, it is possible. Furthermore, in one aspect of the present invention, a novel battery can be provided.

[0026] Furthermore, one aspect of the present invention is not limited to these effects. For example, one aspect of the present invention In some cases, or depending on the circumstances, it may have effects other than those listed above. Yes. Or, for example, one aspect of the present invention may, depending on the circumstances, These effects may not always be present. [Brief explanation of the drawing]

[0027] [Figure 1] A diagram illustrating the method for producing lithium-containing complex phosphates. [Figure 2] Schematic diagram of lithium-containing complex phosphate. [Figure 3] A diagram showing an example of a secondary battery and an example of an electrode. [Figure 4] A diagram showing an example of a secondary battery. [Figure 5] A diagram showing an example of a secondary battery. [Figure 6] A diagram showing an example of a secondary battery. [Figure 7] A diagram showing an example of a secondary battery. [Figure 8] A diagram showing an example of a method for manufacturing a secondary battery. [Figure 9] A diagram showing an example of a method for manufacturing a secondary battery. [Figure 10] A diagram showing an example of a method for manufacturing a secondary battery. [Figure 11] A diagram illustrating the radius of curvature. [Figure 12] A diagram illustrating the radius of curvature. [Figure 13] A diagram illustrating a coin-type rechargeable battery. [Figure 14] A diagram illustrating a cylindrical rechargeable battery. [Figure 15] A diagram illustrating a flexible, laminate-type secondary battery. [Figure 16] A diagram illustrating an example of an energy storage device. [Figure 17] A diagram illustrating an example of an energy storage device. [Figure 18] A diagram illustrating an example of an energy storage device. [Figure 19] A diagram illustrating an example of an energy storage device. [Figure 20] A diagram illustrating an example of an energy storage device. [Figure 21] A diagram illustrating application forms of energy storage devices. [Figure 22] A block diagram illustrating one aspect of the present invention. [Figure 23] A conceptual diagram illustrating one aspect of the present invention. [Figure 24] A circuit diagram illustrating one aspect of the present invention. [Figure 25] A circuit diagram illustrating one aspect of the present invention. [Figure 26] A conceptual diagram illustrating one aspect of the present invention. [Figure 27] Block diagram illustrating one aspect of the present invention [Figure 28] A flowchart illustrating one aspect of the present invention. [Figure 29] Perspective, top, and cross-sectional views illustrating an example of a secondary battery configuration. [Figure 30] A diagram illustrating an example of a method for manufacturing a secondary battery. [Figure 31] Perspective, top, and cross-sectional views illustrating an example of a secondary battery configuration. [Figure 32] A diagram illustrating an example of a method for manufacturing a secondary battery. [Figure 33] SEM image of lithium-containing complex phosphate. [Figure 34] SEM image of lithium-containing complex phosphate. [Figure 35] XRD spectrum of lithium-containing complex phosphate. [Figure 36] Histogram of particle sizes for lithium-containing complex phosphates. [Modes for carrying out the invention]

[0028] The following describes an embodiment of one aspect of the present invention. However, the present invention has many different aspects. It can be implemented in various ways, and without departing from the spirit and scope of the present invention, it can be implemented in various forms. Those skilled in the art will readily understand that the form and details can be changed in various ways. Therefore, this implementation It is not to be interpreted as being limited to the description of the form.

[0029] Note that the words "membrane" and "layer" may differ in some cases or depending on the situation. Therefore, they can be interchanged. For example, the term "conductive layer" can be replaced with "conductive film." In some cases, it may be possible to change the term to "insulating film". Alternatively, for example, the term "insulating film" may be used. In some cases, it may be possible to change the term to "insulating layer."

[0030] In the figures described herein, the positive electrode, negative electrode, active material layer, separator, and outer casing are shown separately. The size, thickness, etc., of each individual component may be exaggerated for the sake of clarity in the explanation. Yes. Therefore, each component is not necessarily limited to its size, nor is the relationship between each component limited. It is not limited to relative size.

[0031] Furthermore, in the configuration of one aspect of the present invention described herein, the same part or similar function The same reference numeral is used consistently across different drawings for parts that share the same characteristics, and explanations of their repetition are omitted. Also, when referring to parts with similar functions, the hatch pattern is the same, and in particular, the markings are used. The number may not be assigned.

[0032] In this specification, the term "energy storage device" refers to all elements and devices that have an energy storage function. For example, lithium-ion secondary batteries and other rechargeable batteries (also called secondary batteries) This includes muon capacitors and electric double-layer capacitors.

[0033] Furthermore, the descriptions of the embodiments for carrying out this invention can be used in appropriate combinations. Cut.

[0034] (Embodiment 1) In this embodiment, a method for producing lithium-containing composite phosphate, which is one aspect of the present invention, is described. This will be explained using Figure 1.

[0035] In step S201a, the lithium compound is weighed. Also in step S201b... Next, weigh the phosphorus compound. Also, in step S201c, iron(II) compound , manganese(II) compounds, cobalt(II) compounds, and nickel(II) compounds ( Below, weigh one or more of the compounds referred to as M(II).

[0036] Typical examples of lithium compounds include lithium hydroxide hydrate (LiOH·H2O) and chloride. Lithium (LiCl), lithium carbonate (Li2CO3), lithium acetate (LiCH3CO3) Examples include (O), lithium oxalate ((COOLi)2), etc.

[0037] Typical examples of phosphorus compounds include phosphoric acid such as orthophosphate (H3PO4) and hydrogen phosphate. Ammonium((NH4)2HPO4), ammonium dihydrogen phosphate(NH4H2PO4) Examples include ammonium hydrogen phosphate, etc.

[0038] Typical examples of iron(II) compounds include iron chloride tetrahydrate (FeCl2·4H2O) and iron sulfate. Examples include heptahydrate (FeSO4·7H2O) and iron acetate (Fe(CH3COO)2).

[0039] A typical example of a manganese(II) compound is manganese chloride tetrahydrate (MnCl2·4H2 O), manganese sulfate hydrate (MnSO4·H2O), manganese acetate tetrahydrate (Mn(C) Examples include H3COO)2·4H2O), etc.

[0040] A typical example of a cobalt(II) compound is cobalt chloride hexahydrate (CoCl2·6H2). O), cobalt sulfate heptahydrate (CoSO4·7H2O), cobalt acetate tetrahydrate (Co( Examples include CH3COO)2·4H2O).

[0041] A typical example of nickel(II) compounds is nickel chloride hexahydrate (NiCl2·6H2 O), nickel sulfate hexahydrate (NiSO4·6H2O), nickel acetate tetrahydrate (Ni( Examples include CH3COO)2·4H2O).

[0042] Next, in step S203a, the lithium compound is dissolved in a solvent containing lithium. A solution is formed. Similarly, in steps S203b and S203c, phosphate compounds are formed. Dissolving a substance and an M(II) compound in a solvent forms a phosphorus-containing solution and a M(II)-containing solution. do.

[0043] Water is a solvent that dissolves lithium compounds, phosphorus compounds, and M(II) compounds.

[0044] Next, in step S205, under an atmospheric atmosphere, the lithium formed in step S203a Mix the um-containing solution with the phosphorus-containing solution formed in step S203b, and prepare mixture A. To form.

[0045] Note that instead of mixture A, lithium such as Li3PO4, Li2HPO4, LiH2PO4 can be used. The lithium salt may be dissolved in a solvent such as water to form a solution containing lithium and phosphorus.

[0046] Next, in step S207, the mixed liquid formed in step S205 is used in an atmospheric environment. While stirring A, add the solution containing M(II) dropwise in small amounts to form mixture B.

[0047] In step S205, the lithium-containing solution and the phosphorus-containing solution are each Depending on the concentration, a precipitate may form in mixture A. When adding mixture A dropwise, precipitate may form. If any object is present, the nozzle of the dispensing device may become clogged, potentially hindering dispensing. Therefore, in step S207, while stirring the mixture A, the solution containing M(II) is added. It is preferable to add the liquid dropwise in small amounts.

[0048] Next, in step S209, the mixture B was placed in a heat-resistant and pressure-resistant container such as an autoclave. Afterwards, at a temperature between 100°C and 350°C, and a pressure between 0.1 MPa and 100 MPa for 0.5 hours or less. After heating for up to 24 hours and then cooling, filter the mixture in a heat-resistant and pressure-resistant container, and the resulting solid is separated by water. Wash and dry.

[0049] As a result, olivine-type lithium-containing composite phosphate (LiMPO4 (M is one or more of Fe(II), Ni(II), Co(II), Mn(II))) can be produced with a high yield depending on the type of M(II) compound. As the lithium-containing composite phosphate, LiFePO4, LiNiPO4, LiCoPO4, LiMnPO4, LiFe ,

[0051] , ,

[0050] , , , , , Ni b PO4, LiFe a Co b PO4, LiFe a Mn b PO4, LiNi a Co b PO4 , LiNi a Mn b PO4 (a + b is 1 or less, 0 < a < 1, 0 < b < 1), LiFe c N i d Co e PO4, LiFe c ]>Ni d Mn e PO4, LiNi c Co d Mn e PO4 (c + d + e is 1 or less, 0 < c < 1, 0 < d < 1, 0 < e < 1), LiFe f Ni g Co h M n i PO4 (f + g + h + i is 1 or less, 0 < f < 1, 0 < g < 1, 0 < h < 1, 0 < i < 1) etc. can be obtained as appropriate. Also, the lithium-containing composite phosphate obtained by this embodiment may be a single crystal grain.

[0050] Here, the shape of the lithium-containing composite phosphate obtained by the production method shown in FIG. 1 will be described. FIG. 2 shows a schematic diagram of the lithium-containing composite phosphate produced according to one aspect of the present invention. FIG. 2

[0051] ​ Figures (A-1) through 2(A-6) are bird's-eye views, and Figures 2(B-1) through 2(B-6) are cross-sectional views. Yes. Figure 2(B-1) shows a cross-section of Figure 2(A-1), and Figure 2(B-2) shows a cross-section of Figure 2(A-2). Figure 2(B-3) shows a cross-section of Figure 2(A-3), and Figure 2(B-4) shows a cross-section of Figure 2( Figure 2(B-5) shows a cross-section of A-4), and Figure 2(B-6) shows a cross-section of Figure 2(A-5). This shows a cross-section of Figure 2(A-6). A lithium-containing composite phosphorus prepared according to one aspect of the present invention. As shown in Figure 2, the salt is placed between the plate-shaped structure 200 and the plate-shaped structure 202 in a prismatic shape. The structure has a structure 204 and a gap between the plate-shaped structure 200 and the plate-shaped structure 202. In some cases, it may be constructed in a plate-like manner. Furthermore, as shown in Figure 2(A-2) or Figure 2(B-2), There may be multiple prismatic structures 204 between structure 200 and plate-shaped structure 202. Yes. In Figure 2, for the sake of ease of identification, we refer to them as structure 200, structure 202, and structure Although 204 has a different hatching pattern, structures 200, 202, and 20 4 may be made of the same material, and structure 200, structure 202, and structure 204 become one unit. It may constitute a single lithium-containing complex phosphate. It may be manufactured according to one aspect of the present invention. When lithium-containing composite phosphates are used as electrode active materials in secondary batteries, this void The contact area between the lithium-containing complex phosphate and the electrolyte increases. The battery reaction of a secondary battery is... Because it is caused by the insertion and removal of ions at the electrode, the positive electrode and lithium ions As the reaction area increases, the reaction rate between the positive electrode and lithium ions increases. Therefore, two This will allow for an increase in the output of the next battery.

[0052] Furthermore, if the lithium-containing composite phosphate is in the form of a plate-like structure, the plate-like structure of the oxide Lithium diffusion throughout the entire structure is completed quickly. The shape of the plate-like structure has a wide surface and short sides. Because it has this feature, lithium taken in from the wider surface moves by the length of the shorter side. This is because lithium can reach the entire area of ​​the oxide. Therefore, The reaction rate between the electrode and lithium increases, making it possible to increase the output of the secondary battery.

[0053] Furthermore, among the surfaces constituting the plate-like structure of lithium-containing composite phosphate, for example, the surface with the largest area In the outer shape of the larger surface, at least one of the interior angles is 100° or less, and the phosphate is used In the layer prepared using this method, the spacing between the phosphate particles becomes larger. When it gets bigger, the electrolyte can easily enter, and the lithium ions in the electrolyte also move. This is preferable because it makes things easier.

[0054] On the other hand, if all interior angles of the plate-like structure are 100° or more, the plate-like structure is approximately correct Because they have a polygonal or circular shape, the particles are close to each other and the gaps between them are small. This can happen. In such cases, the electrolyte will have difficulty entering the gap, so the electrolyte The movement of lithium ions inside may be inhibited, which can reduce the output of the secondary battery. In some cases, the cellular reaction in a secondary battery is caused by the insertion and removal of ions at the electrodes. Therefore, if the mobility of lithium ions improves, the reaction rate between the positive electrode and lithium will be faster. Yes, it will. Therefore, it will be possible to increase the output of the secondary battery.

[0055] From the above perspective, at least one of the interior angles of the plate-like structure of the phosphate is 10 The angle should be 0° or less, preferably 95° or less, and even more preferably 90° or less.

[0056] As described above, lithium-containing composite phosphate according to one aspect of the present invention is used for lithium-ion energy storage. When used in a pond, the output of the secondary battery can be increased.

[0057] Note that the configurations shown in this embodiment may be appropriately replaced with those shown in other embodiments or examples. They can be used in combination.

[0058] In this embodiment, one aspect of the present invention has been described. Or, other embodiments may be described. In this section, one aspect of the present invention will be described. However, this aspect of the present invention is not limited to these. It is not possible. In other words, various aspects of the invention are described in this embodiment and other embodiments. Therefore, one aspect of the present invention is not limited to a specific aspect. For example, in this embodiment As an example, the application to a secondary battery has been shown, but one aspect of the present invention is not limited thereto. No. In some cases, or depending on the circumstances, one aspect of the present invention may be used for various secondary batteries, e.g. For example, lead-acid batteries, lithium-ion polymer rechargeable batteries, nickel-metal hydride batteries, nickel-metal hydride batteries. Dominium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide batteries, solid-state batteries, air It can also be applied to batteries, etc. Or, it can be applied to various energy storage devices. For example, it can be applied to primary batteries, capacitors, lithium-ion capacitors, etc. It is also possible. Or, for example, depending on the circumstances, one aspect of the present invention This does not have to be applied to secondary batteries. Also, in one aspect of the present invention, lithium-containing composite lithium Although an example of a case containing an acid salt has been shown, one aspect of the present invention is not limited thereto. In some cases, or depending on the situation, in one aspect of the present invention, even if it has materials of various types Good. Or, for example, depending on the circumstances, in one aspect of the present invention, It does not need to contain a thium-containing complex phosphate.

[0059] (Embodiment 2) This embodiment describes a secondary battery according to one aspect of the present invention and a method for manufacturing the same. .

[0060] <<Configuration and Assembly of Secondary Batteries>> Figure 3(A) shows a secondary battery 500, which is one embodiment of the present invention. As an example, a thin secondary battery form is shown, but the secondary battery according to one aspect of the present invention is not limited to this. I can't.

[0061] As shown in Figure 3(A), the secondary battery 500 consists of a positive electrode 503, a negative electrode 506, and a separator 50 7, and the outer casing 509. The secondary battery 500 has a positive lead 510 and a negative lead 5 It may also have 11. The joint 518 is joined to the outer circumference of the outer casing 509 by heat compression bonding. It is the part that...

[0062] Figures 4(A) and 4(B) show an example of a cross-sectional view between the dashed line A1 and A2 in Figure 3(A). These are shown. Figures 4(A) and (B) show secondary circuits fabricated using a set of positive electrode 503 and negative electrode 506. The cross-sectional structures of the 500 battery are shown separately.

[0063] As shown in Figures 4(A) and (B), the secondary battery 500 has a positive electrode 503, a negative electrode 506, and a separate It has a positive electrode 507, an electrolyte 508, and an outer casing 509. The separator 507 is positive electrode 50 It is located between 3 and the negative electrode 506. The inside of the outer casing 509 is filled with electrolyte 508.

[0064] The positive electrode 503 includes a positive electrode active material layer 502 and a positive electrode current collector 501. The negative electrode 506 is a negative electrode It includes an active material layer 505 and a negative electrode current collector 504. The active material layer is shaped on one or both sides of the current collector. It should be done. The separator 507 is located between the positive electrode current collector 501 and the negative electrode current collector 504. ru.

[0065] A battery cell only needs to have one or more positive and negative electrodes. For example, a battery cell may have: A laminated structure consisting of multiple positive electrodes and multiple negative electrodes can also be used.

[0066] Figure 5(A) shows another example of the cross-sectional view between the dashed line A1 and A2 in Figure 3(A). Figure 5(B) shows a cross-sectional view between the dashed line B1 and B2 in Figure 3(A).

[0067] Figures 5(A) and (B) show a secondary battery 50 made using multiple sets of positive electrode 503 and negative electrode 506. The cross-sectional structure of 0 is shown. There is no limit to the number of electrode layers that secondary battery 500 has. In combination, it can be made into a secondary battery with a larger capacity. Also, the number of electrode layers is small. In some cases, this allows for a thinner design and a rechargeable battery with excellent flexibility.

[0068] Figures 5(A) and (B) show a positive electrode 5 having a positive electrode active material layer 502 on one side of the positive electrode current collector 501. Two 03s and two positive electrodes 503 having positive electrode active material layers 502 on both sides of the positive electrode current collector 501 And, an example in which three negative electrodes 506, each having a negative electrode active material layer 505 on both sides of a negative electrode current collector 504, are used. This shows that the secondary battery 500 has 6 layers of positive electrode active material 502 and 6 layers of negative electrode active material 5 It has 05. Note that in Figures 5(A) and (B), the separator 507 is shown as a bag-shaped example, The separator 507 may be in the shape of a strip or an accordion.

[0069] Furthermore, in Figure 5, a positive electrode having positive electrode active material layers 502 on both sides of the positive electrode current collector 501 is This can be replaced with two positive electrodes, each having a positive electrode active material layer 502 on one side of the positive electrode current collector 501. Preferred. Similarly, a negative electrode having a negative electrode active material layer 505 on both sides of a negative electrode current collector 504, It is preferable to replace the negative electrode with two negative electrodes, each having a negative electrode active material layer 505 on one side of the negative electrode current collector 504. It seems so. The secondary battery 500 shown in Figure 6 has the positive electrode active material layer 502 attached to the positive electrode current collector 501. The surfaces that are not attached to each other, as well as the surfaces on which the negative electrode active material layer 505 of the negative electrode current collector 504 is not attached. The two officers are facing each other and touching. This configuration allows the secondary battery 500 to When curved, the interface between the two positive electrode current collectors 501 and the interface between the two negative electrode current collectors 504 This acts as a sliding surface, which can alleviate the stress generated inside the secondary battery 500.

[0070] Next, Figure 3(B) shows an external view of the positive electrode 503. The positive electrode 503 is connected to the positive electrode current collector 501 and It has a positive electrode active material layer 502.

[0071] Figure 3(C) also shows an external view of the negative electrode 506. The negative electrode 506 is connected to the negative electrode current collector 504 and It has a negative electrode active material layer 505.

[0072] Here, the positive electrode 503 and the negative electrode 506 are stacked together, with multiple positive electrodes or multiple negative electrodes interacting with each other. It is preferable to have a tab region for electrical connection. Furthermore, the tab region may contain electrode rings. It is preferable to electrically connect the codes.

[0073] As shown in Figure 3(B), it is preferable that the positive electrode 503 has a tab region 281. A portion of region 281 is preferably welded to the positive lead 510. Tab region 281 is It is preferable that there is a region in which the positive electrode current collector 501 is exposed. By welding the positive lead 510 to the region, the contact resistance can be further reduced. Furthermore, Figure 3(B) shows an example where the positive electrode current collector 501 is exposed across the entire tab region 281. This shows that the tab region 281 may have a positive electrode active material layer 502 in part.

[0074] As shown in Figure 3(C), it is preferable that the negative electrode 506 has a tab region 282. A portion of region 282 is preferably welded to the negative electrode lead 511. Tab region 282 is It is preferable that there is a region in which the negative electrode current collector 504 is exposed. By welding the negative electrode lead 511 to the region, the contact resistance can be further reduced. Furthermore, Figure 3(C) shows an example where the negative electrode current collector 504 is exposed across the entire tab region 282. However, the tab region 282 may have a negative electrode active material layer 505 in part.

[0075] Note that Figure 3(A) shows an example where the ends of the positive electrode 503 and the negative electrode 506 are roughly aligned, but The electrode 503 may have a portion that is located outside the end of the negative electrode 506.

[0076] In the secondary battery 500, the area of ​​the region of the negative electrode 506 that does not overlap with the positive electrode 503 is smaller. preferable.

[0077] Figure 4(A) shows an example where the end of the negative electrode 506 is located inside the positive electrode 503. By using this configuration, all of the negative electrodes 506 are superimposed on the positive electrodes 503, or the positive electrode of the negative electrode 506 The area of ​​the region that does not overlap with 503 can be reduced.

[0078] Alternatively, in the secondary battery 500, the areas of the positive electrode 503 and the negative electrode 506 are approximately the same. This is preferable. For example, the surfaces of the positive electrode 503 and the negative electrode 506 facing each other with the separator 507 in between. The products are preferably approximately the same. For example, the positive products opposite each other across the separator 507 It is preferable that the area of ​​the electrode active material layer 502 and the area of ​​the negative electrode active material layer 505 are approximately the same.

[0079] For example, as shown in Figures 5(A) and (B), the area of ​​the surface of the positive electrode 503 on the separator 507 side. It is preferable that the surface area of ​​the negative electrode 506 on the separator 507 side is approximately the same. The area of ​​the negative electrode 506 side of 03 and the area of ​​the positive electrode 503 side of negative electrode 506 are approximately the same. This reduces the area of ​​the negative electrode 506 that does not overlap with the positive electrode 503 (or ideally...) It can be eliminated, and is preferred because it can reduce the irreversible capacity of the secondary battery 500. Alternatively, as shown in Figures 5(A) and (B), the separator 50 of the positive electrode active material layer 502 The area of ​​the side facing 7 and the area of ​​the side facing the separator 507 of the negative electrode active material layer 505 are approximately the same. It is preferable.

[0080] Furthermore, as shown in Figures 5(A) and (B), the ends of the positive electrode 503 and the negative electrode 506 are roughly aligned. It is preferable that the ends of the positive electrode active material layer 502 and the negative electrode active material layer 505 be roughly aligned. This is preferable.

[0081] Furthermore, Figure 4(B) shows an example where the end of the positive electrode 503 is located inside the negative electrode 506. By using such a configuration, all of the positive electrodes 503 are stacked with the negative electrodes 506, or the positive electrodes 503 The area of ​​the region that does not overlap with the negative electrode 506 can be reduced. The end of the negative electrode 506 is positive If the terminal is located inside the end of terminal 503, the current will concentrate at the end of negative terminal 506. For example, when current concentrates on a part of the negative electrode 506, lithium is produced on the negative electrode 506. Precipitation can occur. Reduce the area of ​​the region of the positive electrode 503 that does not overlap with the negative electrode 506. This suppresses the concentration of current in a portion of the negative electrode 506. This allows, for example, This is preferable because it suppresses the deposition of lithium on the negative electrode 506.

[0082] As shown in Figure 3(A), it is preferable that the positive lead 510 be electrically connected to the positive electrode 503. Similarly, it is preferable to electrically connect the negative lead 511 to the negative electrode 506. The positive lead 510 and the negative lead 511 are exposed to the outside of the outer casing 509, and are electrically connected to the outside. It functions as a terminal for making contact.

[0083] Alternatively, the positive electrode current collector 501 and the negative electrode current collector 504 serve as terminals to obtain electrical contact with the outside. It can also serve as a divider. In that case, without using electrode leads, the positive electrode current collector 501 and the negative electrode current collector are used. A portion of the polar current collector 504 may be positioned so as to be exposed to the outside from the outer casing 509.

[0084] Furthermore, in Figure 3(A), the positive lead 510 and the negative lead 511 are the same as those of the secondary battery 500. Although they are arranged on the side, as shown in Figure 7, the positive lead 510 and the negative lead 511 are secondary The batteries 500 may be placed on different sides of the battery. Thus, a secondary battery according to one aspect of the present invention is an electric battery. Because the pole leads can be freely positioned, there is a high degree of design freedom. Therefore, this is one aspect of the present invention. This can increase the design flexibility of products using secondary batteries. Furthermore, one aspect of the present invention This can increase the productivity of products using secondary batteries.

[0085] ≪Examples of methods for manufacturing secondary batteries≫ Next, an example of a method for manufacturing a secondary battery 500, which is one aspect of the present invention, will be shown using Figures 8 to 10. I will explain.

[0086] First, the positive electrode 503, the negative electrode 506, and the separator 507 are stacked. Specifically, the positive electrode 5 Place the separator 507 on top of 03. Then, place the negative electrode 506 on top of the separator 507. Arrange them. If two or more sets of positive and negative electrodes are used, a separator 50 is also placed on top of the negative electrode 506. After placing 7, place the positive electrode 503. In this way, separator 507 is connected to the positive electrode 503 and the negative electrode. Positive electrode 503 and negative electrode 506 are stacked alternately, sandwiched between electrodes 506.

[0087] Alternatively, the separator 507 may be made into a bag shape. By enclosing the electrode with the separator 507... This makes the electrode less susceptible to damage during the manufacturing process, which is preferable.

[0088] First, the positive electrode 503 is placed on the separator 507. Next, the separator 507 is shown in Figure 8. Fold along the dashed line in A), and sandwich the positive electrode 503 with separator 507. We have explained an example where the positive electrode 503 is sandwiched between separators 507, but what about the negative electrode 506? You can also enclose it with 07.

[0089] Here, the outer peripheral portion of the separator 507 on the outside of the positive electrode 503 is joined, and the separator 507 It is preferable to make it bag-shaped (or envelope-shaped). Contact of the outer circumference of separator 507 The joining may be done using adhesives, or by ultrasonic welding or heat-induced fusion. That's good too.

[0090] Next, the outer periphery of the separator 507 is joined by heating. Figure 8(A) shows the joint 514. As shown, the positive electrode 503 can be covered with the separator 507 in this way.

[0091] Next, as shown in Figure 8(B), the negative electrode 506 and the positive electrode 503 covered by the separator are... They are stacked alternately. Also, the positive lead 510 and negative lead 511 having a sealing layer 115 are prepared To prepare.

[0092] Next, as shown in Figure 9(A), the tab region 281 of the positive electrode 503 has a sealing layer 115. Connect the positive lead 510. Figure 9(B) shows an enlarged view of the connection. Apply pressure to the joint 512. By applying ultrasonic waves while adding [a certain force], the tab region 281 of the positive electrode 503 and the positive electrode lead 510 are electrically [treated]. Connected by air (ultrasonic welding). At this time, a curved portion 513 is provided in the tab region 281. stomach.

[0093] By providing the curved portion 513, when external force is applied to the secondary battery 500 after it has been manufactured, This can alleviate stress. Therefore, the reliability of the secondary battery 500 can be improved. ru.

[0094] Using a similar method, the tab region 282 of the negative electrode 506 and the negative electrode lead 511 are electrically connected. It can be connected.

[0095] Next, the positive electrode 503, the negative electrode 506, and the separator 507 are placed on the outer casing 509.

[0096] Next, fold the outer casing 509 along the dashed line near the center of the outer casing 509 in Figure 9(C). bend.

[0097] Figure 10 shows the joint 118, which is the area where the outer periphery of the exterior body 509 is joined by heat compression bonding. The outer periphery of the outer casing 509, excluding the inlet 119 for introducing the electrolyte 508, is sealed by heat compression. The electrodes are joined together. During the heat-compression bonding process, the sealing layer on the electrode leads also melts, and the electrode leads and the outer casing 5 It can be fixed between 09 and 509. Also, the airtightness between the outer casing 509 and the electrode lead can be improved. It can be improved.

[0098] Then, under a reduced pressure atmosphere or an inert gas atmosphere, the desired amount of electrolyte 508 is inlet 1 Insert 19 into the inside of the outer casing 509. Finally, seal the inlet 119 by heat sealing. Combine them. In this way, a thin rechargeable battery, the secondary battery 500, can be manufactured.

[0099] After manufacturing the secondary battery 500, it is preferable to perform aging. Aging conditions An example is explained below. First, charge at a rate of 0.001C to 0.2C. Perform the following. The temperature should be, for example, above room temperature and below 50°C. At this time, the decomposition of the electrolyte will occur. Furthermore, if gas is generated, and that gas accumulates inside the cell, the electrolyte will come into contact with the electrode surface. This results in areas where the reaction cannot occur. In other words, the effective reaction area of ​​the electrode decreases, and the effective area This corresponds to an increase in resistance.

[0100] When the resistance becomes excessively high, the charging voltage increases in proportion to the electrode resistance, and the negative electrode potential decreases. In cases where lithium is inserted into the graphite, lithium is simultaneously deposited on the graphite surface. There is a possibility that this lithium deposition may lead to a decrease in capacity. For example, lithium deposition Afterward, if a film or other substance grows on the surface, the lithium deposited on the surface can no longer be re-eluted. This results in the formation of lithium that does not contribute to the capacity. Also, the deposited lithium physically collapses. Furthermore, if conductivity with the electrodes is lost, lithium that does not contribute to the capacity will still be produced. Therefore, to prevent the negative electrode potential from reaching the lithium potential due to the increase in charging voltage, the gas is released. This is preferable.

[0101] To release the gas, for example, you can cut a part of the casing of a thin battery and open it up. If the outer casing has expanded due to gas, it is preferable to reshape the outer casing. Additionally, electrolyte may be added as needed before resealing.

[0102] Furthermore, after degassing, the temperature should be higher than room temperature, preferably 30°C to 60°C. More preferably at a temperature of 35°C to 50°C, for example, for a period of 1 hour to 100 hours, It may be kept in a charged state. During the initial charging, the electrolyte that decomposes on the surface forms a film. Therefore, for example, by holding it at a temperature higher than room temperature after degassing, it is formed. It is also possible that the coating may become denser.

[0103] ≪Positive electrode configuration≫ Next, the components and materials used in a secondary battery according to one aspect of the present invention will be described. First, the positive electrode will be explained using Figure 4(A). The positive electrode consists of a positive electrode active material layer 502 and a positive electrode Includes current collector 501.

[0104] The positive electrode active material used in the positive electrode active material layer 502 is a carrier such as lithium ions. Materials that allow for ion insertion and removal can be used, for example, olivine-type crystal structures Examples include lithium-containing materials having a layered rock salt-type crystalline structure or a spinel-type crystalline structure. It is possible.

[0105] For example, lithium iron phosphate (LiFePO4) shown in Example 1 is safe, stable, and high volume. Factors such as quantity density, high potential, and the presence of lithium ions that can be extracted during initial oxidation (charging) of the positive electrode active material. It is desirable because it satisfies the requirements in a balanced way.

[0106] The positive electrode active material, along with the negative electrode active material, plays a central role in the battery reaction of a secondary battery, and carrier ions It is a substance that releases and absorbs. In order to extend the lifespan of secondary batteries, irreversible battery reactions are necessary. It is preferable that the material has a small capacity involved in the reaction and is a material with high charge-discharge efficiency. preferable.

[0107] Since the active material comes into contact with the electrolyte, it reacts with the electrolyte, and the active material is lost as a result of the reaction. When this process occurs, the capacity of the secondary battery decreases, therefore, in order to realize a secondary battery with less degradation, It is desirable that such reactions do not occur within secondary batteries.

[0108] As conductive additives for electrodes, acetylene black (AB), graphite particles, and ker Using materials such as Bonn nanotubes, reduced graphene oxide (RGO), and fullerenes. It is possible.

[0109] Conductive additives can form an electrical conduction network within the electrode. This allows the electrical conduction pathway between the positive electrode active materials to be maintained. By adding an electrolytic additive, a positive electrode active material layer 502 with high electrical conductivity can be realized. It is possible.

[0110] In addition, polyimide is used as a binder, in addition to polyvinylidene fluoride (PVDF), which is a typical example. Polytetrafluoroethylene, polyvinyl chloride, ethylene propylene diene Mer, styrene-butadiene rubber, acrylonitrile-butadiene rubber, fluororubber, po Uses vinyl acetate, polymethyl methacrylate, polyethylene, nitrocellulose, etc. It is possible.

[0111] The binder content relative to the total amount of positive electrode active material layer 502 is 1 wt% to 10 wt%. Preferably, 2wt% to 8wt%, and 3wt% to 5wt%. Furthermore, the content of the conductive additive relative to the total amount of the positive electrode active material layer 502 is 1 wt%. Preferably, the amount is 10 wt% or less, and more preferably 1 wt% to 5 wt%.

[0112] When forming the positive electrode active material layer 502 using a coating method, the positive electrode active material, binder, and conductive aid are used. The agent and dispersion medium are mixed to prepare an electrode slurry, which is then applied to the positive electrode current collector 501 and dried. Yes.

[0113] Furthermore, the positive electrode current collector 501 may be made of metals such as stainless steel, gold, platinum, aluminum, and titanium. These alloys and other materials have high conductivity and do not alloy with carrier ions such as lithium. It can also be used. Furthermore, silicon, titanium, neodymium, scandium, molybdenum, etc. Aluminum alloys to which elements that improve heat resistance have been added can be used. It may also be formed from a metallic element that reacts with silicon to form a silicide. Metal elements that form silicides include zirconium, titanium, hafnium, and vanadium. Dium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel, etc. There are positive electrode current collectors in foil form, plate form (sheet form), mesh form, perforated metal form, and expansive form. Shapes such as solid metal can be used as appropriate.

[0114] The positive electrode of a secondary battery can be manufactured through the above process.

[0115] ≪Configuration of the negative electrode≫ Next, the negative electrode will be explained using Figure 4(A). The negative electrode consists of a negative electrode active material layer 505 and a negative electrode cluster. It includes an electric body 504. The process of forming the negative electrode is described below.

[0116] As for the negative electrode active material used in the negative electrode active material layer 505, carbon-based materials include graphite and easily graphitized materials. Carbon-forming carbon (soft carbon), non-graphitizable carbon (hard carbon), carbon nanotubes Examples include graphene, carbon black, etc. Mesocarbon microbeads are also used as a form of graphite. Artificial graphite such as MCMB, coke-based artificial graphite, pitch-based artificial graphite, and spheroidized natural black Natural graphite exists, such as lead. Graphite can also exist in various forms, including flaky and spherical shapes. .

[0117] In addition to carbon-based materials, the negative electrode active material can also be charged and discharged through alloying and dealloying reactions with lithium. Materials capable of carrying out the reaction can also be used. For example, Ga, Si, Al, Ge, A material containing at least one of the following: Sn, Pb, Sb, Bi, Ag, Zn, Cd, In, etc. It can be used. Such elements have a larger capacity compared to carbon, and silicon in particular is theoretical. The high capacity of 4200mAh / g is desirable. Such alloy materials (compounds) using these elements are desirable. Examples of system materials include Mg2Si, Mg2Ge, Mg2Sn, SnS2, and V2Sn. 3, FeSn2, CoSn2, Ni3Sn2, Cu6Sn5, Ag3Sn, Ag3Sb, Ni2MnSb, CeSb3, LaSn3, La3Co2Sn7, CoSb3, InSb Examples include SbSn, etc.

[0118] Furthermore, as negative electrode active materials, SiO, SnO, SnO2, titanium dioxide (TiO2), and lithium Lithium titanium oxide (Li4Ti5O 12 ), lithium-graphite intercalation compound (Li x C6), Niobium pentoxide (Nb2O5), tungsten oxide (WO2), molybdenum oxide (MoO2) Oxides such as ) can be used.

[0119] Furthermore, the negative electrode active material has a Li3N type structure, which is a lithium and transition metal binitride. Li 3-x M x N (where M is Co, Ni, or Cu) can be used. For example, Li2 .6 Co 0.4 The N3 has a large charge / discharge capacity (900mAh / g, 1890mAh / cm²). 3 ) This indicates a preference.

[0120] When a lithium and transition metal binitride is used, lithium is included in the negative electrode active material, so the positive electrode active It can be combined with materials that do not contain lithium, such as V2O5 and Cr3O8. Furthermore, even when using a lithium-containing material as the positive electrode active material, the positive electrode active material should be treated in advance. By removing the contained lithium, a complex nitride of lithium and a transition metal is used as the negative electrode active material. You can use it.

[0121] Furthermore, materials that undergo a conversion reaction can also be used as the negative electrode active material. For example, Lithium oxide, such as cobalt oxide (CoO), nickel oxide (NiO), and iron oxide (FeO). Transition metal oxides that do not undergo alloying reactions may be used as the negative electrode active material. Materials that can produce a response include Fe2O3, CuO, Cu2O, RuO2, and Cr2O. Third-order oxides, CoS 0.89Sulfides such as NiS and CuS, Zn3N2, Cu3N, G Nitrides such as e3N4, phosphides such as NiP2, FeP2, CoP3, FeF3, BiF3 This can also occur with fluorides such as these.

[0122] For example, the negative electrode active material should have a particle size of 50 nm to 100 μm. .

[0123] Furthermore, in both the positive electrode active material layer 502 and the negative electrode active material layer 505, there are multiple active material materials. The materials may be used in combination in specific proportions. By using multiple materials in the active material layer... This allows for more detailed selection of the active material layer's performance.

[0124] As conductive additives for electrodes, acetylene black (AB), graphite particles, and ker Using materials such as Bonn nanotubes, reduced graphene oxide (RGO), and fullerenes. It is possible.

[0125] Conductive additives can form an electrical conduction network within the electrode. This allows for the maintenance of electrical conduction pathways between the negative electrode active materials. By adding an electrolytic additive, a negative electrode active material layer 505 with high electrical conductivity can be realized. It is possible.

[0126] In addition, polyimide is used as a binder, in addition to polyvinylidene fluoride (PVDF), which is a typical example. Polytetrafluoroethylene, polyvinyl chloride, ethylene propylene diene Mer, styrene-butadiene rubber, acrylonitrile-butadiene rubber, fluororubber, po Uses vinyl acetate, polymethyl methacrylate, polyethylene, nitrocellulose, etc. It is possible.

[0127] The binder content relative to the total amount of the negative electrode active material layer 505 is between 1 wt% and 10 wt%. Preferably, 2wt% to 8wt%, and 3wt% to 5wt%. Furthermore, the content of the conductive additive relative to the total amount of the negative electrode active material layer 505 is 1 wt%. Preferably, the amount is 10 wt% or less, and more preferably 1 wt% to 5 wt%.

[0128] Next, a negative electrode active material layer 505 is formed on the negative electrode current collector 504. When forming the 505 matrix, the negative electrode active material, binder, conductive additive, and dispersion medium are mixed together. Prepare the rally and apply it to the negative electrode current collector 504 and let it dry. Also, if necessary after drying, Pressing may be performed.

[0129] The negative electrode current collector 504 is made of stainless steel, gold, platinum, zinc, iron, copper, titanium, and tantalum. Metals such as these, and their alloys, which have high conductivity and can be alloyed with carrier ions such as lithium. Materials that do not react with silicon can be used. Also, metals that react with silicon to form silicides. It may also be formed from elements. Examples of metallic elements that react with silicon to form silicides include di ruconium, titanium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum These include tungsten, cobalt, nickel, etc. The negative electrode current collector 504 is foil-shaped, plate-shaped (sheet metal). Shapes such as T-shape, mesh, cylindrical, coil, perforated metal, expanded metal, etc. The following can be used as appropriate. The negative electrode current collector 504 has a thickness of 5 μm or more and 30 μm or less. It is recommended to use this. Also, use graphite or similar material on a part of the surface of the electrode current collector. A coating layer may be provided.

[0130] The negative electrode of the secondary battery can be manufactured through the above processes.

[0131] ≪Configuration of Separator≫ The separator 507 will be described. As the material of the separator 507, paper, non-woven fabric, glass fiber, or synthetic fibers such as nylon (polyamide), vinylon (polyvinyl alcohol-based fiber ), polyester, acrylic, polyolefin, polyurethane, etc. may be used. However, it is necessary to select a material that does not dissolve in the electrolyte solution described later.

[0132] More specifically, as the material of the separator 507, for example, fluorine-based polymers, polyethers such as polyethylene oxide and polypropylene oxide, polyolefins such as polyethylene and polypropylene, polyacrylonitrile, polyvinylidene chloride, polymethyl methacrylate, polymethyl acrylate, polyvinyl alcohol, polymethacrylonitrile, polyvinyl acetate, polyvinyl pyrrolidone, polyethylene imine, polybutadiene, polystyrene, polyisoprene, polyurethane-based polymers and their derivatives, cellulose, paper, non-woven fabric, glass fiber, one selected from these can be used alone or in combination of two or more.

[0133] ≪Configuration of Electrolyte Solution≫

[0134] The electrolyte solution 508 that can be used in the secondary battery according to one aspect of the present invention is preferably a non-aqueous solution (solvent) containing an electrolyte (solute).

[0135] As the solvent of the electrolyte solution 508, a material in which carrier ions can move is used. For example, an aprotic organic solvent is preferable, such as ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, chloroethylene carbonate, vinylene carbonate γ-Butyrolactone, γ-Valerolactone, Dimethyl carbonate (DMC), Dietary Carbonate (DEC), ethyl methyl carbonate (EMC), methyl formate, methyl acetate Chil, methyl butyrate, 1,3-dioxane, 1,4-dioxane, dimethoxyethane (DM E) Dimethyl sulfoxide, diethyl ether, methyl diglyme, acetonitrile, One of the following: benzonitrile, tetrahydrofuran, sulfolane, sultone, or a combination of these. Two or more of these can be used in any combination and ratio.

[0136] Furthermore, by using a polymer material that gels as the solvent for the electrolyte 508, leakage can be addressed. This increases safety. Furthermore, it enables the secondary battery to be made thinner and lighter. Typical examples of molecular materials include silicone gels, acrylic gels, acrylonitrile gels, and polycrystalline polymers. Polyethylene oxide gels, polypropylene oxide gels, fluorine polymer gels, etc. There is.

[0137] Furthermore, as the solvent for the electrolyte, an ionic liquid (also called a room-temperature molten salt) that is flame-retardant and slow to evaporate is used. By using one or more of these, the internal temperature of the secondary battery can be prevented from being short-circuited or overcharged. Even if the temperature rises, it can prevent the secondary battery from rupturing or catching fire. This ensures the safety of the secondary battery. It can enhance overall integrity.

[0138] The above explanation describes the case where the carrier ion is a lithium ion. However, carrier ions other than lithium ions can also be used. In the case of alkali metal ions and alkaline earth metal ions as carrier ions, electrolytes As for the above lithium salt, instead of lithium, an alkali metal (for example, sodium or potassium, etc.), an alkaline earth metal (for example, calcium, strontium, barium , beryllium, magnesium, etc.) may be used.

[0139] In addition, the electrolyte used in the secondary battery is preferably a highly purified electrolyte with a low content of particulate dust and elements other than the constituent elements of the electrolyte (hereinafter also simply referred to as "impurities"). Specifically, the mass ratio of impurities to the electrolyte is preferably 1% or less, more preferably 0.1% or less, and even more preferably 0.01% or less. Also, additives such as vinylene carbonate may be added to the electrolyte.

[0140] 1]]When using lithium ions as carriers for the electrolyte dissolved in the above solvent, for example, LiPF6, LiClO4, LiAsF6, LiBF4, LiAlCl4, Li SCN, LiBr, LiI, Li2SO4, Li2B Cl 10 10 12 Cl1 2, LiCF3SO3, LiC4F9SO3, LiC(CF3SO2)3, LiC(C2 F5SO2)3, LiN(CF3SO2)2, LiN(C4F9SO2)(CF3SO2 ), LiN(C2F5SO2)2, etc., can be used alone or in any combination and ratio of two or more of these.

[0141] Note that the electrolyte may react with the current collector of the positive electrode and corrode the positive electrode current collector. To prevent such corrosion, several wt% of LiPF6 may be added to the electrolyte. The surface of the positive electrode current collector A non-conductive film may form, and this non-conductive film may suppress the reaction between the electrolyte and the positive electrode current collector. However, in order to avoid dissolving the positive electrode active material layer, the concentration of LiPF6 is preferably 10 wt% or less. It is preferable to have a concentration of 5 wt% or less, or more preferably 3 wt% or less.

[0142] ≪Graphene Compounds≫ In one embodiment of the present invention, graphene compounds are used in each component constituting the energy storage device. This is possible. Graphene compounds, as described below, can be broadly selected in terms of structure and properties through modification. Therefore, depending on the component to which the graphene compound is to be applied, desirable properties can be obtained. It can be expressed. Also, because graphene compounds have high mechanical strength, graphene The compound can also be applied to each component that makes up a flexible energy storage device. This section explains lafen compounds.

[0143] Graphene is composed of a single atomic layer of carbon atoms, with π bonds between the carbon atoms. A material in which two to 100 layers of graphene are stacked is sometimes called multigraphene. Graphene and multigraphene, for example, in the longitudinal direction or along the long axis in a plane The length is 50 nm to 100 μm or 800 nm to 50 μm.

[0144] In this specification, compounds having graphene or multigraphene as a basic skeleton are used. "Graphene compound" It is also called "d"). Graphene compounds include graphene and multigraphene. .

[0145] The following provides a detailed explanation of graphene compounds.

[0146] Graphene compounds, for example, graphene or multigraphene, contain atoms other than carbon, or a compound modified with an atomic group containing atoms other than carbon. Also, graphene or Multigraphene is modified with carbon-based atomic groups such as alkyl groups and alkylenes. It may also be a compound. Furthermore, the atomic group that modifies graphene or multigraphene is placed These may be called substitution groups, functional groups, or characteristic groups. Here, in this specification, modification means , through substitution reactions, addition reactions or other reactions, graphene, multigraphene, gra Fen compounds, or graphene oxide (described later), containing atoms other than carbon, or containing atoms other than carbon This refers to introducing a group of atoms that are primarily carbon, or a group of atoms that are primarily carbon.

[0147] Furthermore, even if the front and back surfaces of graphene are modified by different atoms or groups of atoms, Good. Also, in multigraphene, each layer is modified with different atoms or groups of atoms. It's okay if it's not allowed.

[0148] An example of graphene modified with the aforementioned atoms or groups of atoms is one containing oxygen or oxygen. Examples include graphene or multigraphene modified with functional groups containing oxygen. Examples of functional groups include epoxy groups, carboxyl groups and other carbonyl groups, or hydroxyl groups. Examples include graphene compounds modified with oxygen or oxygen-containing functional groups. It is sometimes called graphene oxide. Also, in this specification, graphene oxide is multilayer This also includes graphene oxide.

[0149] As an example of modification in graphene oxide, we will explain the silylation of graphene oxide. First, in a nitrogen atmosphere, graphene oxide is placed in a container, and n-butylamine is added to the container. Add (C4H9NH2) and stir at 60°C for 1 hour. Next, add toluene to the container. Furthermore, alkyltrichlorosilane is added as a silylating agent, and the mixture is exposed to a nitrogen atmosphere. Then, stir at 60°C for 5 hours. Next, add more toluene to the container and filter by suction to solidify. A powder is obtained and dispersed in ethanol. This is then filtered by suction to obtain a solid powder. It is then dispersed in acetone. Furthermore, this is filtered by suction to obtain a solid powder, and the liquid component is... The process vaporizes to obtain silylated graphene oxide.

[0150] Furthermore, the modification is not limited to silylation, nor is the silylation limited to the method described above. In addition to introducing atoms or groups of atoms of a certain type, multiple types of modifications are applied, and multiple types of atoms are introduced. A child or group of atoms may be introduced. By introducing a specific group of atoms into the graphene compound, The physical properties of graphene compounds can be altered. Therefore, the applications of graphene compounds are... By applying the desired modifications accordingly, the graphene compound can be intentionally made to exhibit the desired properties. It can be done.

[0151] Next, an example of a method for producing graphene oxide will be described. Graphene oxide is the same as the graphene described above. Alternatively, it can be obtained by oxidizing multigraphene. Or, graphene oxide can be oxidized. Graphite can be obtained by separating it. Graphite oxide is obtained by oxidizing graphite. This can be obtained by further modifying the graphene oxide with the aforementioned atoms or groups of atoms. You may do so.

[0152] The compound obtained by reducing graphene oxide is called "RGO (Reduced Graphene) It is sometimes called "graphene oxide." Note that RGO contains graphene oxide. Not all of the oxygen was eliminated; some oxygen or oxygen-containing atoms remained bonded to the carbon. In some cases, RGO may exist. For example, RGO may contain epoxy groups, carboxyl groups, or other carbonyl groups. Alternatively, it may have functional groups such as hydroxyl groups.

[0153] Graphene compounds are formed in the form of a single sheet, with multiple graphene compounds partially overlapping. It may be so. When such a graphene compound is called a graphene compound sheet. There are graphene compound sheets, for example, with a thickness of 0.33 nm to 10 mm. Preferably, it has a region greater than 0.34 nm and less than or equal to 10 μm. Graphene compound sheet The term refers to atoms other than carbon, groups of atoms containing atoms other than carbon, or alkyl groups that are primarily composed of carbon. It may also be modified with atomic groups such as the graphene compound sheet. Each layer of numbers may be modified by different atoms or groups of atoms.

[0154] Graphene compounds include not only six-membered rings composed of carbon, but also five-membered rings composed of carbon, and carbon It may have a multi-membered ring of seven or more members composed of the following: This can result in regions where lithium ions can pass through.

[0155] Alternatively, for example, multiple graphene compounds may be aggregated to form a sheet-like structure.

[0156] Because graphene compounds have a planar shape, surface contact is possible.

[0157] Graphene compounds can have high conductivity even when thin, and graphene compounds can combine through surface contact. This can increase the contact area between materials, or between graphene compounds and active materials. Therefore, even with a small amount per unit volume, conductive paths can be efficiently formed.

[0158] On the other hand, graphene compounds can also be used as insulators. For example, graphene compounds The sheet can be used as a sheet-like insulator. Here, for example, graphene oxide is It may have higher insulating properties compared to unoxidized graphene compounds. Also, the atomic group Modified graphene compounds can have their insulating properties enhanced depending on the type of atomic group used for modification. It may be possible.

[0159] Herein, the graphene compound may have a graphene precursor. Graphene precursors are substances used to manufacture graphene. The graphene precursor may include, for example, the aforementioned graphene oxide or graphite oxide. .

[0160] Furthermore, graphene containing alkali metals, and graphene containing elements other than carbon, such as oxygen. These are sometimes referred to as graphene analogs. In this specification, graphene compounds include Graphene. This also includes rafen analogs.

[0161] Furthermore, the graphene compounds described herein contain atoms, atomic groups, and their interlayers. It may have an on. Furthermore, the graphene compound may have atoms, atomic groups, and their on between the layers. By having ON, the physical properties of graphene compounds, such as electrical conductivity and ionic conductivity, are affected. It may change. Also, the interlayer distance may increase.

[0162] Graphene compounds possess excellent electrical properties, including high conductivity, as well as high flexibility and high It possesses excellent physical properties, such as high mechanical strength, and may also have other properties. Depending on the type of modification, the compound can be made extremely electrically conductive and act as an insulator. Yes. Furthermore, graphene compounds have a planar shape. Graphene compounds have contact resistance. This enables low surface contact.

[0163] <<Outer structure>> Next, the outer casing 509 will be described. The outer casing 509 may be made of, for example, polyethylene, polyp On a film made of materials such as polypropylene, polycarbonate, ionomer, and polyamide, A highly flexible metal thin film such as aluminum, stainless steel, copper, or nickel is provided, and further, the metal An insulating synthetic resin such as polyamide resin or polyester resin is used as the outer surface of the outer casing on a thin film. A film with a three-layer structure and a membrane can be used. It blocks the permeation of electrolytes and gases, ensures insulation, and also has electrolyte resistance. Fold the outer casing inward and overlap, or place the inner surfaces of the two outer casings facing each other. By applying heat repeatedly, the inner material melts, fusing the two outer casings together and sealing. A stopper structure can be fabricated.

[0164] If the area where the outer casing is fused or otherwise formed to create a sealing structure is considered the sealing part, then the outer casing is folded inward. When bent and stacked, a sealing portion is formed in areas other than the fold, and the first region of the outer casing, The structure is formed by fusing the first region and the second region that overlaps with it. If this occurs, a sealing portion is formed on the entire outer circumference by methods such as heat fusion.

[0165] Flexible rechargeable batteries If a flexible material is selected from the materials of each component shown in this embodiment, Flexible secondary batteries can be fabricated. In recent years, research on deformable devices and Development is thriving. As a secondary battery to be used in such devices, a flexible secondary battery There is a demand for ponds.

[0166] A curved secondary battery with two films as the outer casing, sandwiching the electrodes, electrolyte, etc., and 1805 microelectrolyte. In this case, the radius of curvature 1802 of the film 1801 on the side closer to the center of curvature 1800 of the secondary battery is , smaller than the radius of curvature 1804 of film 1803 on the side farther from the center of curvature 1800 (Figure) 11(A)). If the secondary battery is curved to make the cross-section arc-shaped, the center of curvature is close to 1800. Compressive stress is applied to the surface of the film, while tensile stress is applied to the surface of the film far from the center of curvature of 1800. Stress is applied (Figure 11(B)).

[0167] When a flexible secondary battery is deformed, a large stress is placed on the outer casing, but the surface of the outer casing When a pattern is formed on the surface with concave or convex portions, the deformation of the secondary battery causes compressive stress and tensile stress. Even if tension stress is applied, the effects of strain can be suppressed. Therefore, The next battery has a radius of curvature of the outer casing on the side closer to the center of curvature that is 30 mm, preferably 10 mm. It can be transformed within the enclosure.

[0168] The radius of curvature of a surface will be explained using Figure 12. In Figure 12(A), the curved surface 1700 In the plane 1701 obtained by cutting the curve, a portion of the curve 1702 contained in the curved surface 1700 is an arc of a circle. By approximating this, the radius of the circle is set to the radius of curvature of 1703, and the center of the circle is set to the center of curvature of 1704. Figure 12(B) shows a top view of the curved surface 1700. Figure 12(C) shows the curved surface 1 on the plane 1701. The cross-sectional view of 700 is shown. When cutting a curved surface with a plane, the angle of the plane relative to the curved surface and The radius of curvature of the curve appearing in the cross-section will differ depending on the cutting position, but this specification, etc. Let's define the smallest radius of curvature as the radius of curvature of the surface.

[0169] Furthermore, the cross-sectional shape of a secondary battery is not limited to a simple arc shape, but may have a shape in which part of it is an arc. It is possible to create shapes such as the one shown in Figure 11(C), a wavy shape (Figure 11(D)), or an S-shape. It is also possible to do so. If the curved surface of the secondary battery has a shape with multiple centers of curvature, Among the radii of curvature at each of the centers of curvature, the two surfaces with the smallest radius of curvature The radius of curvature of the outer casing closest to the center of curvature of the outer casing is 30 mm, preferably 10 mm. The secondary battery can be deformed within a certain range.

[0170] The positive electrode active material layer of the secondary battery shown in this embodiment is a positive electrode active material layer according to one aspect of the present invention. It is used in this way. Therefore, it is possible to increase the output of secondary batteries.

[0171] This embodiment can be implemented in appropriate combination with other embodiments and examples. be.

[0172] (Embodiment 3) In this embodiment, the structure of a secondary battery according to one aspect of the present invention is shown in Figures 13 to 14. I will explain by referring to it.

[0173] Coin-type rechargeable battery Figure 13(A) is an external view of a coin-type (single-layer flat-type) secondary battery, and Figure 13(B) is... This is a cross-sectional view.

[0174] The coin-type rechargeable battery 300 consists of a positive electrode casing 301, which also serves as the positive terminal, and a negative electrode casing, which also serves as the negative terminal. 302 is insulated and sealed by a gasket 303 made of polypropylene or the like. The positive electrode 304 consists of a positive electrode current collector 305 and a positive electrode active material layer 306 provided in contact with it. It is formed by the positive electrode active material layer 306, which enhances the adhesion of the positive electrode active material in addition to the positive electrode active material. It contains a binder for this purpose, a conductive additive for enhancing the conductivity of the positive electrode active material layer, etc. That's fine.

[0175] The material shown in Embodiment 1 can be used as the positive electrode active material.

[0176] Furthermore, the negative electrode 307 consists of a negative electrode current collector 308 and a negative electrode active material layer provided in contact with it. Formed by 309. The negative electrode active material layer 309 contains the negative electrode active material, as well as the adhesion of the negative electrode active material. Binding agents (binders) to enhance conductivity, conductive additives to enhance conductivity of the negative electrode active material layer, etc. It may have a separator 31 between the positive electrode active material layer 306 and the negative electrode active material layer 309. It contains 0 and an electrolyte (not shown).

[0177] The positive electrode can 301 and negative electrode can 302 are made of nickel and aluminum, which are corrosion-resistant to the electrolyte. Metals such as um, titanium, or alloys thereof, or alloys of these with other metals (e.g., stainless steel) Materials such as stainless steel can be used. In addition, nickel and aluminum can be used to prevent corrosion by the electrolyte. It is preferable to coat with aluminum or the like. Positive electrode can 301 is with positive electrode 304, and negative electrode can 302 is with negative Connect each of the poles 307 electrically.

[0178] These negative electrode 307, positive electrode 304, and separator 310 are impregnated with the electrolyte, as shown in Figure 13(B). As shown, with the positive electrode can 301 at the bottom, the positive electrode 304, separator 310, negative electrode 307, and negative The electrode cans 302 are stacked in this order, and the positive electrode can 301 and the negative electrode can 302 are connected via a gasket 303. The coin-shaped rechargeable battery 300 is manufactured by crimping the parts together.

[0179] Here, we will use Figure 13(C) to explain the current flow during the charging of a secondary battery. Using lithium When a secondary battery is considered as a closed circuit, the movement of lithium ions and the flow of current are in the same direction. In addition, in lithium-ion secondary batteries, the anode and cathode are used during charging and discharging. The cathode is swapped, and the oxidation and reduction reactions are reversed, thus changing the reaction potential. The electrode with a high reaction potential is called the positive electrode, and the electrode with a low reaction potential is called the negative electrode. Therefore, in this specification... In this case, whether charging or discharging, or even when applying a reverse pulse current, Even when an electric current is flowing, the positive electrode is called the "positive electrode" or "+ electrode (positive pole)," and the negative electrode is called the "positive pole." This will be referred to as the "negative electrode" or "- electrode (minus electrode)". Related to oxidation and reduction reactions. Using the terms anode and cathode, the difference between charging and discharging is significant. This could be reversed and cause confusion. Therefore, the anode and cathode The term cathode will not be used in this specification. When using terms such as positive electrode () or cathode, specify whether it is during charging or discharging, and the positive electrode ( The corresponding polarity (positive or negative) should also be indicated.

[0180] The charger is connected to the two terminals shown in Figure 13(C), and the secondary battery 400 is charged. As the secondary battery 400 charges, the potential difference between the electrodes increases. In Figure 13(C), the secondary battery From the external terminal of battery 400, the current flows towards the positive electrode 402, and within the secondary battery 400, the positive electrode Current flows from 402 to the negative electrode 404, and from the negative electrode to the external terminal of the secondary battery 400. The direction of flow is considered the positive direction. In other words, the direction in which the charging current flows is considered the direction of the current. .

[0181] Cylindrical rechargeable battery Next, an example of a cylindrical secondary battery will be explained with reference to Figure 14. Cylindrical secondary battery As shown in Figure 14(A), 600 has a positive electrode cap (battery cover) 601 on its top surface, and on its side and has a battery can (outer casing) 602 on the bottom. These positive electrode cap 601 and battery can ( The outer casing (602) is insulated by a gasket (insulating packing) (610).

[0182] Figure 14(B) is a schematic diagram showing a cross-section of a cylindrical secondary battery. Inside can 602, a strip-shaped positive electrode 604 and a negative electrode 606 are separated by a separator 605. A wound battery element is provided. Although not shown in the diagram, the battery element is centered around the center pin. It is wound up. The battery can 602 is closed at one end and open at the other end. This is a metal such as nickel, aluminum, or titanium that is corrosion-resistant to the electrolyte, or this These alloys or alloys of these with other metals (for example, stainless steel) can be used. Furthermore, to prevent corrosion from the electrolyte, it is preferable to coat the components with nickel, aluminum, etc. Inside the battery can 602, the battery element in which the positive electrode, negative electrode, and separator are wound is It is sandwiched between a pair of opposing insulating plates 608 and 609. A battery element is also provided. The inside of the battery can 602 is filled with a non-aqueous electrolyte (not shown). The non-aqueous electrolyte is A battery similar to that of the IN type rechargeable battery can be used.

[0183] The positive electrode 604 and the negative electrode 606 are manufactured in the same manner as the positive and negative electrodes of the coin-type secondary battery described above. However, since the positive and negative electrodes used in cylindrical secondary batteries are wound, both sides of the current collector They differ in that they form an active material. The positive electrode 604 has a positive electrode terminal (positive electrode current collector lead) 603. The negative terminal (negative current collector lead) 607 is connected to the negative terminal 606. Both 603 and the negative terminal 607 can be made of metal materials such as aluminum. The positive terminal 603 is connected to the safety valve mechanism 612, and the negative terminal 607 is connected to the bottom of the battery can 602. Resistance welding is performed. The safety valve mechanism 612 is a PTC element (Positive Tempera The positive electrode cap 601 is electrically connected via the ture Coefficient) 611. The safety valve mechanism 612 activates when the rise in the internal pressure of the battery exceeds a predetermined threshold, thereby activating the positive electrode valve. This disconnects the electrical connection between cap 601 and positive electrode 604. Also, PTC element 6 Element 11 is a thermal resistance element whose resistance increases when the temperature rises, and the increase in resistance causes current to flow. This prevents abnormal heat generation by limiting the amount. The PTC element contains barium titanate (Ba TiO3-based semiconductor ceramics and the like can be used.

[0184] The positive electrode active material layer of the secondary battery shown in this embodiment is a positive electrode active material layer according to one aspect of the present invention. It is used in this way. Therefore, it is possible to increase the output of secondary batteries.

[0185] Figure 15 also shows an example of mounting a flexible laminate-type secondary battery in an electronic device. Electronic devices that utilize energy storage devices with flexible shapes include, for example, televisions. Devices (also called televisions or television receivers), monitors for computers, etc. Digital cameras, digital video cameras, digital photo frames, mobile phones (mobile phones, (Also called mobile phone devices), portable game consoles, personal information terminals, sound playback devices, pachinko machines, etc. Examples include large game consoles.

[0186] Furthermore, energy storage devices with flexible shapes can be installed in the interior or exterior walls of houses and buildings, or in automobiles. It can also be incorporated along the curved surfaces of the interior or exterior.

[0187] Figure 15(A) shows an example of a mobile phone. Mobile phone 7400 has a housing 7401 In addition to the display unit 7402 incorporated into it, there are operation buttons 7403, an external connection port 7404, and It is equipped with a speaker 7405, a microphone 7406, etc. The mobile phone 7400 also has a battery storage function. It has device 7407.

[0188] Figure 15(B) shows the mobile phone 7400 in a curved state. Mobile phone 740 When the 0 is deformed by an external force and the whole thing is curved, the energy storage device located inside is revealed. The 7407 is also bent. Figure 15(C) shows the state of the bent energy storage device 7407 at that time. As shown in ( ). The energy storage device 7407 is a laminate-type secondary battery.

[0189] Figure 15(D) shows an example of a bangle-type display device. The portable display device 7100 is The device comprises a housing 7101, a display unit 7102, operation buttons 7103, and a power storage device 7104. Figure 15(E) also shows the state of the bent energy storage device 7104.

[0190] <<Example of an energy storage device structure>> Examples of the structure of an energy storage device will be explained using Figures 16 to 20.

[0191] Figures 16(A) and 16(B) show external views of the energy storage device. The energy storage device is a circuit It has a circuit board 900 and a secondary battery 913. A label 910 is attached to the secondary battery 913. Furthermore, as shown in Figure 16(B), the energy storage device has terminal 951 and terminal 952 It also has antenna 914 and antenna 915.

[0192] The circuit board 900 has terminal 911 and circuit 912. Terminal 911 is connected to terminal 951 It is connected to terminal 952, antenna 914, antenna 915, and circuit 912. Multiple terminals 911 are provided, and each of the multiple terminals 911 is designated as a control signal input terminal and a power supply terminal. You could also do this.

[0193] The circuit 912 may be provided on the back surface of the circuit board 900. Furthermore, the antenna 914 and The antenna 915 is not limited to a coil shape, but may also be linear, plate-shaped, etc. Planar antenna, aperture antenna, traveling wave antenna, EH antenna, magnetic field antenna, dielectric Antennas such as antennas may be used. Alternatively, antenna 914 or antenna 915 may be used. Alternatively, a flat conductor may be used. This flat conductor functions as one of the conductors for electric field coupling. This is possible. In other words, as one of the two conductors of the capacitor, You may activate antenna 914 or antenna 915. This will allow only electromagnetic and magnetic fields to be generated. Alternatively, power can be exchanged using an electric field.

[0194] The line width of antenna 914 is preferably larger than the line width of antenna 915. Furthermore, the amount of power received can be increased by antenna 914.

[0195] The energy storage device has a layer 916 between antennas 914 and 915 and the secondary battery 913. The layer 916 can prevent, for example, the influence of the secondary battery 913 on the electromagnetic field. It has the function of [doing something]. For layer 916, a magnetic material can be used, for example.

[0196] Note that the structure of the energy storage device is not limited to that shown in Figure 16.

[0197] For example, as shown in Figures 17(A-1) and 17(A-2), Figures 16(A) and 16 Even if an antenna is provided on each of the opposing pairs of surfaces of the secondary battery 913 shown in (B) Good. Figure 17(A-1) is an external view of the pair of surfaces as seen from one side, and Figure 17( A-2) is an external view of the pair of surfaces as seen from the other side. Note that Figure 16(A) and For the same parts as the energy storage device shown in Figure 16(B), see Figures 16(A) and 16(B). The explanation of the energy storage device can be used as appropriate.

[0198] As shown in Figure 17(A-1), a layer 916 is sandwiched between one of the pair of surfaces of the secondary battery 913. An inlet 914 is provided, and as shown in Figure 17(A-2), a pair of sides of the secondary battery 913 On the other side, an antenna 915 is provided with a layer 917 in between. Layer 917 is, for example, a secondary battery 91 It has the function of preventing the influence of 3 on the electromagnetic field. As for layer 917, for example A magnetic material can be used.

[0199] By adopting the above structure, the size of both antenna 914 and antenna 915 can be increased. It is possible.

[0200] Alternatively, as shown in Figures 17(B-1) and 17(B-2), Figures 16(A) and 16( Of the secondary battery 913 shown in B), separate antennas are provided on each of the opposing pair of surfaces. This is also acceptable. Figure 17(B-1) is an external view of the pair of surfaces as seen from one side, and Figure 17 (B-2) is an external view of the pair of surfaces as seen from the other side. Note that Figure 16(A) and For the same parts as the energy storage device shown in Figure 16(B), see Figures 16(A) and 16(B). The explanation of the energy storage device shown can be used as appropriate.

[0201] As shown in Figure 17(B-1), a layer 916 is sandwiched between one of the pair of surfaces of the secondary battery 913. An antenna 914 and an antenna 915 are provided, and as shown in Figure 17(B-2), a secondary battery An antenna 918 is provided on the other side of the pair of faces of 913, with layer 917 in between. Antenna 91 8, for example, has the function of being able to communicate data with external devices. Antenna 91 For example, antennas with shapes applicable to antennas 914 and 915 are applied to 8. This is possible. The communication method between the energy storage device and other equipment via antenna 918 is N Applying response methods that can be used between energy storage devices and other equipment, such as FC (Fuel Cell) systems. It is possible.

[0202] Alternatively, as shown in Figure 18(A), the secondary battery 913 shown in Figures 16(A) and 16(B) may be used. A display device 920 may be provided. The display device 920 is connected to terminal 911 via terminal 919. They are electrically connected. Note that a label 910 is not provided in the area where the display device 920 is provided. This is also acceptable. Furthermore, for the same parts as the energy storage device shown in Figures 16(A) and 16(B), The explanation of the energy storage device shown in Figures 16(A) and 16(B) can be used as appropriate.

[0203] The display device 920 displays, for example, an image indicating whether or not it is charging, an image indicating the amount of stored power, etc. It may be shown. The display device 920 may be, for example, electronic paper, liquid crystal display device, or electronic A luminescent (also known as EL) display device can be used. For example, an electronic paper By using this method, the power consumption of the display device 920 can be reduced.

[0204] Alternatively, as shown in Figure 18(B), the secondary battery 913 shown in Figures 16(A) and 16(B) A sensor 921 may be provided. The sensor 921 receives electrical signals from terminal 911 via terminal 922. It is connected to the same part as the energy storage device shown in Figures 16(A) and 16(B). Therefore, the explanation of the energy storage device shown in Figures 16(A) and 16(B) can be appropriately referenced.

[0205] Examples of sensors 921 include displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, and light. Liquid, magnetism, temperature, chemicals, sound, time, hardness, electric field, electric current, voltage, power, radiation, flow It should have the ability to measure quantity, humidity, gradient, vibration, odor, or infrared radiation. By providing the sensor 921, for example, data indicating the environment in which the energy storage device is located can be collected. It can also detect (temperature, etc.) and store it in the memory within circuit 912.

[0206] Furthermore, an example of the structure of the secondary battery 913 will be explained using Figures 19 and 20.

[0207] The secondary battery 913 shown in Figure 19(A) has terminals 951 and 952 inside the housing 930. It has a wound body 950. The wound body 950 is impregnated with an electrolyte inside the housing 930. Terminal 952 is in contact with the housing 930, and terminal 951 is in contact with the housing by using insulating material, etc. It is not in contact with the body 930. Note that in Figure 19(A), for convenience, the housing 930 is separated. As shown in the diagram, in reality the wound body 950 is covered by the housing 930, and terminals 951 and 95 2 extends outside the casing 930. The casing 930 is made of a metal material (e.g., aluminum). Materials such as lum or resin can be used.

[0208] Furthermore, as shown in Figure 19(B), the housing 930 shown in Figure 19(A) is made of multiple materials. They may be formed. For example, the secondary battery 913 shown in Figure 19(B) has a housing 930a and a housing 9 30b is bonded together, and the area enclosed by the housing 930a and housing 930b is wound up 9 50 is provided.

[0209] For the casing 930a, insulating materials such as organic resin can be used. In particular, the antenna By using a material such as organic resin on the surface where the electric field of the secondary battery 913 is formed, Shielding can be suppressed. Furthermore, if the shielding of the electric field by the housing 930a is small, the housing 930a Antennas such as antenna 914 and antenna 915 may be installed inside. For example, metal materials can be used.

[0210] Furthermore, the structure of the wound body 950 is shown in Figure 20. The wound body 950 consists of a negative electrode 931 and a positive electrode. It has poles 932 and separators 933. The coiled body 950 sandwiches the separators 933. The negative electrode 931 and the positive electrode 932 are stacked on top of each other, and the stacked sheet is wound up to form a wound body. Furthermore, the stacking of the negative electrode 931, the positive electrode 932, and the separator 933 is further multiplied. You can do it multiple times.

[0211] The negative electrode 931 is connected to terminal 911 shown in Figure 16 via either terminal 951 or terminal 952. The positive terminal 932 is connected to terminal 91 shown in Figure 16 via terminal 951 and the other terminal 952. It connects to 1.

[0212] ≪Example of electrical equipment: Example of equipment installed in a vehicle≫ Next, we will show an example of installing a secondary battery in a vehicle. When a secondary battery is installed in a vehicle, the hybrid Hybrid electric vehicles (HEVs), electric vehicles (EVs), or plug-in hybrid electric vehicles (PHEVs) This enables the realization of next-generation clean energy vehicles such as those mentioned above.

[0213] Figure 21 illustrates a vehicle using one aspect of the present invention. Figure 21(A) shows automobile 8 The 100 is an electric vehicle that uses an electric motor as its power source for driving. Alternatively, The vehicle can appropriately select and use an electric motor and an engine as power sources for propulsion. It is a hybrid vehicle. By using one aspect of the present invention, it is possible to repeatedly charge and discharge it. This makes it possible to realize a vehicle that can do this. Furthermore, the automobile 8100 has an energy storage device. It not only drives the electric motor, but also the headlights 8101 and interior lights (not shown). It can supply power to light-emitting devices such as ).

[0214] Furthermore, the energy storage device is used for the speedometer, tachometer, and other displays of the 8100 automobile. It can supply power to the device. In addition, the energy storage device is the navigation system of the automobile 8100. It can supply power to semiconductor devices such as junction gate systems.

[0215] The automobile 8200 shown in Figure 21(B) is plugged into the energy storage device of the automobile 8200. It can be charged by receiving power from an external charging facility using methods such as contactless power supply. Figure 21(B) shows the power supply from the ground-mounted charging device 8021 to the vehicle 8200. This indicates that the electrical device is being charged via cable 8022. The charging device 8021 is This could be a charging station located in a commercial facility, or it could be a power source in a home. For example, plug-in technology allows the 8200 car to be powered by an external power supply. The energy storage device can be charged. Charging is done via a conversion device such as an AC / DC converter. This can be done by converting alternating current (AC) power to direct current (DC) power.

[0216] Although not shown in the diagram, a power receiving device is mounted on the vehicle, and power is supplied wirelessly from a ground-based power transmission device. It can also be charged by doing so. In this contactless power supply method, power transmission equipment is installed in roads or exterior walls. By incorporating this, charging can be performed not only when the vehicle is stopped but also while it is in motion. Furthermore, this contactless power supply... This method may be used to transmit and receive power between vehicles. Furthermore, the exterior of the vehicle Solar panels may be installed to charge the energy storage device when the vehicle is stopped or in motion. Electromagnetic induction or magnetic resonance methods can be used to supply power to it.

[0217] According to one aspect of the present invention, the cycle characteristics of the energy storage device are improved, thereby enhancing reliability. This can be done. Furthermore, according to one aspect of the present invention, the characteristics of the energy storage device can be improved, This means the energy storage device itself can be made smaller and lighter. This contributes to reducing the vehicle's weight, thus improving its driving range. Furthermore, it can be mounted on the vehicle. The energy storage device can also be used as a power source other than for vehicles. In this case, the power demand This allows us to avoid using commercial power during peak hours.

[0218] This embodiment can be implemented in appropriate combination with other embodiments.

[0219] In this specification, etc., the figures or text described in a particular embodiment may differ from the actual figures or text. And, if at least one specific example is given, it is possible to derive a higher-level concept from that specific example. This will be easily understood by those skilled in the art. Therefore, in one embodiment, If at least one specific example is described in a diagram or text, the higher-level example of that specific example is... This is also disclosed as one aspect of the invention and may constitute one aspect of the invention. It is a Noh play. And one aspect of that invention can be said to be clear.

[0220] Furthermore, in this specification, etc., at least the contents shown in the figures (or even just a part of the figures) It is disclosed as one aspect of the invention, and it is possible to constitute one aspect of the invention. Yes. Therefore, if a certain content is described in a diagram, it does not need to be stated in text. Even if it is not disclosed, its content is disclosed as one aspect of the invention, and does not constitute one aspect of the invention. It is possible to do so. Similarly, a diagram showing only a part of the figure can also be considered as one aspect of the invention. It is disclosed in this way and can constitute one aspect of the invention. One aspect of the invention can be said to be clear.

[0221] (Embodiment 4) A battery that can be used in combination with a battery cell containing the materials described in the above embodiment Your unit (Battery Management Unit: BMU) and the battery For transistors suitable for the circuits constituting the control unit, please refer to Figures 22 to 28. This will be explained. In this embodiment, the battery of an energy storage device having battery cells connected in series Let me explain the control unit.

[0222] When multiple battery cells connected in series are repeatedly charged and discharged, the space between each battery cell As a result, variations in charge and discharge characteristics occur, causing the capacity (output voltage) of each battery cell to differ. In a series connection of multiple battery cells, the total discharge capacity is reduced by the capacity of the smallest battery cell. It depends. If there is variation in the capacity of each battery cell, the overall capacity during discharge will be smaller. Furthermore, if charging is performed based on a battery cell with a smaller capacity, there is a risk of insufficient charging. Charging based on a large number of battery cells may lead to overcharging.

[0223] Therefore, the battery control unit of an energy storage device having battery cells connected in series will be in a state of insufficient charge. It also has a function to equalize the capacity variations between battery cells, which can cause overcharging. Circuit configurations to equalize the capacitance variations between them include resistor methods, capacitor methods, or industrial There are various methods such as the Kuta method, but here we will use a transistor with a small off-current to compensate for the variation in capacitance. I will explain by giving an example of a circuit configuration that can be assembled.

[0224] As a transistor with a low off-current, a transistor having an oxide semiconductor in the channel formation region is an example. A transistor (OS transistor) is preferred. An OS transistor with a small off-current is used in the energy storage device. By using it in the circuit configuration of the battery control unit, the amount of charge leaking from the battery is reduced, and This can suppress the decrease in capacity over time.

[0225] The oxide semiconductor used in the channel formation region is In-M-Zn oxide (where M is Ga, Sn, Y, Zr, La, Ce, or Nd are used. They are used to form oxide semiconductor films. In the target, if the atomic ratio of the metal elements is In:M:Zn=x1:y1:z1, 、 x1 / y1 is between 1 / 3 and 6, and moreover, between 1 and 6, and z1 / y1 is 1 It is preferable that z1 / y1 is between 3 and 6, and more preferably between 1 and 6. By setting the upper limit to 6 or lower, the CAAC-OS film is more easily formed as an oxide semiconductor film.

[0226] Now, let's discuss the CAAC-OS membrane.

[0227] CAAC-OS film is an oxide semiconductor film having multiple c-axis oriented crystalline regions.

[0228] Transmission Electron Microscope (TEM) A composite analysis image of the CAAC-OS film's bright-field image and diffraction pattern (using a scope) Also known as a high-resolution TEM image, multiple crystalline regions can be identified by observing it. On the other hand, high-resolution TEM images also clearly show the boundaries between crystalline parts, i.e., grain boundaries. Also called boundary.) It is not possible to confirm. Therefore, the CAAC-OS membrane is This means that a decrease in electron mobility due to grain boundaries is less likely to occur.

[0229] When observing a high-resolution TEM image of the cross-section of the CAAC-OS film from a direction approximately parallel to the sample surface, In the crystalline region, it can be confirmed that the metal atoms are arranged in layers. Each layer of metal atoms is: The surface (also called the film-forming surface) or the top surface of the CAAC-OS film reflects the unevenness of the surface on which the film is formed. It has a specific shape and is arranged parallel to the surface or top surface of the CAAC-OS film to be formed.

[0230] On the other hand, a high-resolution TEM image of the CAAC-OS film plane was observed from a direction approximately perpendicular to the sample surface. This confirms that in the crystalline region, the metal atoms are arranged in a triangular or hexagonal shape. However, no regularity is observed in the arrangement of metal atoms between different crystalline regions.

[0231] X-ray diffraction (XRD) applied to the CAAC-OS film. When structural analysis is performed using this method, for example, a CAAC-OS film having InGaZnO4 crystals is found. In the out-of-plane analysis, the diffraction angle (2θ) shows a peak near 31°. This peak may appear. This peak is attributed to the (009) plane of the InGaZnO4 crystal. Therefore, the crystals of the CAAC-OS film have c-axis orientation, and the c-axis is approximately aligned with the surface to be formed or the upper surface. It can be confirmed that it is facing vertically.

[0232] Furthermore, the out-of-plane method for CAAC-OS films containing InGaZnO4 crystals. Analysis revealed that in addition to a peak near 2θ = 31°, a peak also appeared near 2θ = 36°. In some cases, this may occur. Peaks near 36° 2θ indicate c-axis orientation in a portion of the CAAC-OS film. This indicates that it contains crystals that do not have [the specified characteristic]. The CAAC-OS film has 2θ near 31°. It is preferable that a peak is observed, and that no peak is observed near 36° for 2θ.

[0233] CAAC-OS films are oxide semiconductor films with low impurity concentrations. The impurities include hydrogen, carbon, These are elements other than silicon and transition metal elements, which are the main components of oxide semiconductor films. In particular, silicon Elements such as ions, which have a stronger bonding force with oxygen than the metal elements that make up oxide semiconductor films, By removing oxygen from the material semiconductor film, the atomic arrangement of the oxide semiconductor film is disrupted, reducing its crystallinity. This is a contributing factor. Also, heavy metals such as iron and nickel, argon, and carbon dioxide have a certain atomic radius. Because of its large molecular radius, when it is contained within an oxide semiconductor film, the oxide semiconductor film This disrupts the atomic arrangement and reduces crystallinity. Furthermore, these impurities are present in oxide semiconductor films. Objects can sometimes act as carrier traps or carrier sources.

[0234] Furthermore, CAAC-OS films are oxide semiconductor films with a low defect level density. For example, oxide Oxygen vacancies in semiconductor films can act as carrier traps or capture hydrogen. It can be a source of carrier activity.

[0235] A low impurity concentration and low defect level density (few oxygen vacancies) is referred to as high-purity intrinsic or This is essentially called high-purity intrinsic. High-purity intrinsic or substantially high-purity intrinsic oxide semiconductor film Because there are fewer carrier sources, the carrier density can be kept low. Therefore, The transistor using this oxide semiconductor film exhibits an electrical characteristic in which the threshold voltage becomes negative. Also called normally-on.) It rarely becomes high-purity intrinsic or substantially high-purity. Highly intrinsic oxide semiconductor films have few carrier traps. Transistors using body membranes exhibit less variation in electrical characteristics and are highly reliable. Furthermore, the charge trapped in the carrier trap of the oxide semiconductor film requires time to be released. It can remain dormant for a long time, behaving almost like a fixed charge. Therefore, the impurity concentration Transistors using oxide semiconductor films with high defect level density have unstable electrical properties. It can happen.

[0236] Furthermore, transistors using CAAC-OS films exhibit electrical characteristics under irradiation with visible light and ultraviolet light. The fluctuations are small.

[0237] OS transistors are transistors that have silicon in the channel formation region (SiT Because it has a larger band gap compared to a transistor, dielectric breakdown occurs when a high voltage is applied. It is difficult. When battery cells are connected in series, a voltage of several hundred volts will be generated, but storage The circuit configuration of a battery control unit applied to such a battery cell in an electrical device is as described above. It is suitable to construct it using OS transistors.

[0238] Figure 22 shows an example of a block diagram of an energy storage device. The energy storage device BT00 shown in Figure 22 is terminal Child pair BT01, terminal pair BT02, switching control circuit BT03, switching circuit BT0 4, the switching circuit BT05, the transformer control circuit BT06, the transformer circuit BT07, and in series It has a battery section BT08 which includes a plurality of connected battery cells BT09.

[0239] Furthermore, in the energy storage device BT00 shown in Figure 22, terminal pair BT01 and terminal pair BT02 are connected. Switching control circuit BT03, switching circuit BT04, switching circuit BT05, and transformer control The section consisting of circuit BT06 and transformer circuit BT07 is called the battery control unit. It is possible.

[0240] The switching control circuit BT03 controls the operation of switching circuits BT04 and BT05. Control. Specifically, the switching control circuit BT03 measures each battery cell BT09. Based on voltage, the battery cells to be discharged (discharge battery cell group) and the battery cells to be charged (charge battery cell group) are selected. Determine the group of pond cells.

[0241] Furthermore, the switching control circuit BT03 controls the determined group of discharge battery cells and the recharge battery cells. Based on the group, control signals S1 and S2 are output. Control signal S1 is output when switching. The signal is output to path BT04. This control signal S1 connects terminal pair BT01 and the group of discharge battery cells. This is a signal that controls the switching circuit BT04 to keep it running. Also, the control signal S2 is for switching The signal is output to the replacement circuit BT05. This control signal S2 is connected to the terminal pair BT02 and the rechargeable battery cell. This is a signal that controls the switching circuit BT05 to connect the group.

[0242] Furthermore, the switching control circuit BT03 is connected to the switching circuit BT04, the switching circuit BT05, and Based on the configuration of the transformer circuit BT07, the terminal pair between BT01 and the group of discharge battery cells, or terminal Control the connection between the BT02 child unit and the rechargeable battery cell group so that terminals with the same polarity are connected to each other. Signal S1 and control signal S2 are generated.

[0243] This section describes the operation of the switching control circuit BT03 in detail.

[0244] First, the switching control circuit BT03 measures the voltage of each of the multiple battery cells BT09. The switching control circuit BT03 then, for example, switches battery cells BT09 with a voltage above a predetermined threshold. High-voltage battery cells (high-voltage cells), battery cells BT09 with a voltage below a predetermined threshold, low-voltage It is identified as a battery cell (low-voltage cell).

[0245] Furthermore, various methods can be used to determine whether a cell is high-voltage or low-voltage. Yes, it is possible. For example, the switching control circuit BT03 selects the most powered battery cell among the multiple battery cells BT09. Using the voltage of the battery cell BT09 with the highest or lowest voltage as a reference, each battery cell BT0 You may also need to determine whether 9 is a high-voltage cell or a low-voltage cell. In this case, the switching control circuit BT03 This determines whether the voltage of each battery cell BT09 is above a predetermined percentage of the reference voltage. By doing so, it is possible to determine whether each battery cell BT09 is a high-voltage cell or a low-voltage cell. Based on this determination, the switching control circuit BT03 then determines the discharge battery cell group and the charging battery Determine the group of cells in the pond.

[0246] Furthermore, within multiple BT09 battery cells, high-voltage and low-voltage cells are mixed together in various states. To obtain. For example, the switching control circuit BT03 is used in a situation where high-voltage cells and low-voltage cells are mixed together. The section where the most high-voltage cells are connected in series is designated as the discharge battery cell group. The replacement control circuit BT03 charges the section where the most low-voltage cells are connected in series. This is a group of battery cells. Furthermore, the switching control circuit BT03 is used when the battery cells are close to being overcharged or over-discharged. Even if you preferentially select BT09 as either a discharge battery cell group or a recharge battery cell group good.

[0247] Here, an example of the operation of the switching control circuit BT03 in this embodiment will be explained using Figure 23. To clarify, Figure 23 is a diagram illustrating an example of the operation of the switching control circuit BT03. For the sake of explanation, Figure 23 shows an example where four BT09 battery cells are connected in series. explain.

[0248] First, in the example in Figure 23(A), if the voltages of battery cells a to d are voltages Va to Vd, This shows the case where Va=Vb=Vc>Vd. In other words, three consecutive high-voltage Voltage cells a through c and one low-voltage cell d are connected in series. In this case, switching The control circuit BT03 determines that three consecutive high-voltage cells a to c are a group of discharge battery cells. Furthermore, the switching control circuit BT03 determines the low-voltage cell d as the rechargeable battery cell group. .

[0249] Next, the example in Figure 23(B) shows the case where Vc > Va = Vb >> Vd. In other words, two consecutive low-voltage cells a and b, one high-voltage cell c, and one over-discharge cell. The nearby low-voltage cell d is connected in series. In this case, the switching control circuit BT03 is The high-voltage cell c is determined to be the discharge battery cell group. Also, the switching control circuit BT03 is low Because voltage cell d is close to over-discharge, instead of using the two consecutive low-voltage cells a and b, The voltage cell d is given priority as the group of rechargeable battery cells.

[0250] Finally, the example in Figure 23(C) shows the case where Va > Vb = Vc = Vd. In other words, one high-voltage cell a is connected in series with three consecutive low-voltage cells b through d. In this case, the switching control circuit BT03 determines that high-voltage cell a is the same as the discharge battery cell group. The switching control circuit BT03 charges three consecutive low-voltage cells b through d. This will be determined as a group of battery cells.

[0251] The switching control circuit BT03 is determined as shown in the examples in Figures 23(A) to (C) above. Based on this, information indicating the group of discharge battery cells to which the switching circuit BT04 is connected is set. The control signal S1 and information indicating the group of rechargeable battery cells to which the switching circuit BT05 is connected are provided. The specified control signal S2 is sent to switching circuits BT04 and BT05. Output each of them.

[0252] The above is a detailed explanation of the operation of the switching control circuit BT03.

[0253] The switching circuit BT04 responds to the control signal S1 output from the switching control circuit BT03. The connection destination of terminal pair BT01 is determined by the switching control circuit BT03 to the discharge battery. Set to group L.

[0254] Terminal pair BT01 consists of a pair of terminals A1 and A2. Switching circuit BT04 This involves connecting either terminal A1 or A2 to the upstream (high current) terminal within the group of discharge battery cells. Connect to the positive terminal of battery cell BT09 located on the (position) side, and the other side to the most discharged battery cell group. By connecting to the negative terminal of battery cell BT09 located downstream (low potential side), the terminal Set the connection destination for BT01. Note that the switching circuit BT04 is set to control signal S1. The location of the discharge battery cells can be recognized using the collected information.

[0255] The switching circuit BT05 responds to the control signal S2 output from the switching control circuit BT03. The connection destination of the terminal pair BT02 is determined by the switching control circuit BT03 to the rechargeable battery. Set to group L.

[0256] Terminal pair BT02 consists of the paired terminals B1 and B2. Switching circuit BT05 This involves connecting either terminal B1 or B2 to the upstream (high current) terminal within the rechargeable battery cell group. Connect to the positive terminal of battery cell BT09 located on the (position) side, and the other side to the most in the group of rechargeable battery cells. By connecting to the negative terminal of battery cell BT09 located downstream (low potential side), the terminal Set the connection destination for BT02. Note that the switching circuit BT05 is set to control signal S2. The location of the battery cell group can be recognized using the collected information.

[0257] Figures 24 and 2 show circuit diagrams illustrating example configurations of switching circuits BT04 and BT05. This is shown in 5.

[0258] In Figure 24, the switching circuit BT04 consists of multiple transistors BT10 and bus BT11 and It has bus BT12. Bus BT11 is connected to terminal A1. Also, bus BT1 2 is connected to terminal A2. The source or drain of multiple transistors BT10 One side is connected to buses BT11 and BT12 alternately, one at a time. The source or drain of each of the multiple transistors BT10 is connected to two adjacent It is connected between the BT09 battery cells.

[0259] Of the multiple transistors BT10, the transistor BT10 located at the very top The other end of the drain is the positive electrode of battery cell BT09, which is located at the uppermost part of battery section BT08. It is connected to the terminal. Also, among the multiple transistors BT10, the one located furthest downstream is... The source or drain of the transistor BT10 is located at the downstream end of the battery unit BT08. It is connected to the negative terminal of battery cell BT09.

[0260] The switching circuit BT04 provides a control signal S1 to the gates of multiple transistors BT10. Accordingly, one of the multiple transistors BT10 connected to bus BT11 and bus B Connect one of the multiple transistors BT10 connected to T12 to make it conductive. This connects the discharge battery cell group to the terminal pair BT01. The positive terminal of battery cell BT09, which is located in the uppermost part of the group, is terminal A1 or A of the terminal pair. It is connected to either of the two. Also, the battery cell located at the downstream end of the discharge battery cell group. The negative terminal of the BT09 is either terminal A1 or A2 of the terminal pair, i.e., the other terminal, i.e., the positive terminal. It connects to the terminal that is not connected to the other terminal.

[0261] It is preferable to use an OS transistor for transistor BT10. Because the off-current is small, it reduces the amount of charge leakage from battery cells that do not belong to the discharge battery cell group. Furthermore, the decrease in capacitance over time can be suppressed. Also, OS transistors are high Dielectric breakdown is less likely to occur when voltage is applied. Therefore, the output voltage of the discharge battery cell group is large. Even if the transistor BT10, which is in a non-conductive state, is connected to the battery cell BT09 and terminals It is possible to isolate BT01 from the other device.

[0262] Furthermore, in Figure 24, the switching circuit BT05 consists of multiple transistors BT13 and current control It has a switch BT14, a bus BT15, and a bus BT16. Buses BT15 and BT 16 is positioned between the multiple transistors BT13 and the current control switch BT14. The source or drain of each of the multiple transistors BT13 alternates every other one. It is connected to buses BT15 and BT16. Also, multiple transistors BT13 The other end of either the source or drain is connected between two adjacent battery cells BT09, respectively. It is.

[0263] Of the multiple transistors BT13, the transistor BT13 located at the very top The other end of the drain is the positive electrode of battery cell BT09, which is located at the uppermost part of battery section BT08. It is connected to the terminal. Also, among the multiple transistors BT13, the one located furthest downstream is... The source or drain of the transistor BT13 is located at the downstream end of the battery unit BT08. It is connected to the negative terminal of battery cell BT09.

[0264] Transistor BT13 uses an OS transistor, similar to transistor BT10. This is preferable. OS transistors do not belong to the rechargeable battery cell group because they have a small off-current. This reduces the amount of charge leaking from the battery cell and suppresses the decrease in capacity over time. It can. Furthermore, OS transistors are less prone to dielectric breakdown when high voltage is applied. Therefore, Even if the voltage for charging the battery cells is high, the transistor BT remains in a non-conductive state. 13 can be used to insulate the battery cell BT09 to which it is connected from the terminal pair BT02.

[0265] The current control switch BT14 has switch pair BT17 and switch pair BT18. One end of the switch to BT17 is connected to terminal B1. In addition, the other end of the switch to BT17 The end is branched by two switches; one switch is connected to bus BT15, and the other... The switch is connected to bus BT16. One end of the switch to BT18 is connected to terminal B2. It is continued. Also, the other end of the switch to BT18 is branched by two switches, one of which One switch is connected to bus BT15, and the other switch is connected to bus BT16. .

[0266] The switches in switch pair BT17 and switch pair BT18 are transistor BT10 And, similar to transistor BT13, it is preferable to use an OS transistor.

[0267] The switching circuit BT05 controls the transistor BT13 and current control according to the control signal S2. By controlling the on / off state combination of switch BT14, the rechargeable battery cell group Connect the terminal to BT02.

[0268] The switching circuit BT05, as an example, connects the rechargeable battery cell group and terminal pair BT0 as follows. Connect to 2.

[0269] The switching circuit BT05 provides a control signal S2 to the gates of multiple transistors BT13. Accordingly, it is connected to the positive terminal of battery cell BT09, which is located in the upstream position among the rechargeable battery cell group. The transistor BT13 is made conductive. Also, the switching circuit BT05 has multiple In accordance with the control signal S2 applied to the gate of transistor BT13, in the group of rechargeable battery cells Transistor BT13 is connected to the negative terminal of battery cell BT09, which is located furthest downstream. To make it conductive.

[0270] The polarity of the voltage applied to terminal pair BT02 is determined by the group of discharge battery cells connected to terminal pair BT01. This may vary depending on the configuration of the transformer circuit BT07. Also, the method for charging the battery cell group To allow current to flow in one direction, the terminal pair BT02 and the group of rechargeable battery cells must have terminals of the same polarity. It is necessary to connect the wire. Therefore, the current control switch BT14 is controlled by the control signal S2, Depending on the polarity of the voltage applied to terminal pair BT02, switch pair BT17 and switch pair BT The system is controlled to switch between each of the 18 connection destinations.

[0271] As an example, a voltage is applied to the terminal pair BT02 such that terminal B1 is the positive terminal and terminal B2 is the negative terminal. Let's explain by listing the conditions in which this is happening. At this time, the battery cell BT09 at the downstream end of the battery unit BT08 If it is a group of rechargeable battery cells, the switch to BT17 will, by the control signal S2, control the battery cells It is controlled to connect to the positive terminal of BT09. That is, the switch to BT17 The switch connected to bus BT16 is turned ON, and the switch is connected to bus BT17. The switch connected to 5 is turned off. Meanwhile, the switch to BT18 receives the control signal S2 This controls the connection to the negative terminal of the battery cell BT09. Switch to BT18 is connected to bus BT15 and the switch to B The switch connected to bus BT16 of T18 is turned off. In this way, the terminal pair Terminals with the same polarity are connected between the BT02 and the rechargeable battery cell group. The direction of the current flowing from the BT02 is controlled to charge the battery cells. It will be done.

[0272] Furthermore, the current control switch BT14 is not the switching circuit BT05, but the switching circuit BT It may be included in 04.

[0273] Figure 25 shows an example configuration of switching circuits BT04 and BT05, which differs from Figure 24. This is a circuit diagram showing the circuit.

[0274] In Figure 25, the switching circuit BT04 consists of multiple transistor pairs BT21 and bus BT24. It also has bus BT25. Bus BT24 is connected to terminal A1. BT25 is connected to terminal A2. One end of the multiple transistor pair BT21 is connected to it. These are branched by transistors BT22 and BT23. Either the source or drain of BT22 is connected to bus BT24. Either the source or drain of the BT23 is connected to the BT25 bus. The other ends of multiple transistor pairs BT21 are connected between two adjacent battery cells BT09. It is connected to the upstream transistor among the multiple transistor pairs BT21. The other end of the converter pair BT21 is connected to the positive terminal of battery cell BT09, which is located at the uppermost part of the battery section BT08. It is connected to the pole terminal. Also, among the multiple transistor pairs BT21, it is located at the furthest downstream end. The other end of the transistor pair BT21 is connected to the battery cell BT0, which is located at the downstream end of the battery section BT08. It is connected to the negative terminal of 9.

[0275] The switching circuit BT04 switches transistor BT22 and transistor according to the control signal S1. By switching the conduction / non-conduction state of BT23, the contact between the transistor and BT21 is Switch the destination to either terminal A1 or terminal A2. For details, see transistor B If T22 is conducting, transistor BT23 will be non-conducting, and its connection point will be the terminal. It becomes child A1. On the other hand, if transistor BT23 is conducting, then transistor BT22 It becomes non-conductive, and its connection point is terminal A2. Transistor BT22 and Trans Which of the BT23 terminals becomes conductive is determined by the control signal S1.

[0276] Two transistor pairs, BT21, are used to connect terminal pair BT01 to the group of discharge battery cells. It can be. In detail, based on the control signal S1, the connection destination of the two transistors to BT21 Once these are determined, the group of discharge battery cells and the terminal pair BT01 are connected. The connections of the two transistor pairs BT21 are such that one is terminal A1 and the other is terminal The system is controlled by control signal S1 to achieve A2.

[0277] The switching circuit BT05 consists of multiple transistor pairs BT31, bus BT34 and bus BT It has 35. Bus BT34 is connected to terminal B1. Bus BT35 is It is connected to terminal B2. One end of each of the multiple transistor pairs BT31 is connected to the transistor It is branched by transistor BT32 and transistor BT33. Transistor BT32 One of the branching ends is connected to bus BT34. Also, transistor BT33 One branching end is connected to bus BT35. Additionally, multiple transistors are paired with BT31. The other end is connected between two adjacent battery cells BT09. Of the transistor pairs BT31, the other end of the transistor pair BT31 located at the uppermost position is It is connected to the positive terminal of battery cell BT09, which is located at the uppermost part of the battery section BT08. Among the multiple transistor pairs BT31, the other transistor pair BT31 located at the furthest downstream The end is connected to the negative terminal of battery cell BT09, which is located at the downstream end of battery section BT08. .

[0278] The switching circuit BT05 switches transistor BT32 and transistor in response to the control signal S2. By switching the conduction / non-conduction state of BT33, the contact between the transistor and BT31 is Switch the destination to either terminal B1 or terminal B2. For details, see transistor B If T32 is conducting, transistor BT33 will be non-conducting, and its connection point will be the terminal. It becomes child B1. Conversely, if transistor BT33 is conducting, then transistor BT32 It becomes non-conductive, and its connection point is terminal B2. Transistor BT32 and Trans Which of the BT33 terminals becomes conductive is determined by the control signal S2.

[0279] To connect the terminal pair BT02 to the battery cell group, two transistor pairs BT31 are used. It can be. In detail, based on the control signal S2, the connection destination of the two transistors to BT31 Once these are determined, the rechargeable battery cell group and the terminal pair BT02 are connected. The connections of each pair of transistors in BT31 are such that one is to terminal B1 and the other is to terminal It is controlled by the control signal S2 so that it becomes B2.

[0280] Furthermore, the connections of the two transistor pairs BT31 are applied to the terminal pair BT02. This is determined by the polarity of the voltage. Specifically, terminal B1 is the positive terminal and terminal B2 is the negative terminal. When such a voltage is applied to terminal pair BT02, the upstream transistor pair BT31 is Transistor BT32 becomes conductive, and transistor BT33 becomes non-conductive. It is controlled by the control signal S2. On the other hand, the downstream transistor pair BT31 is Control the transistor BT33 to be in a conductive state and the transistor BT32 to be in a non-conductive state. It is controlled by signal S2. Also, the voltage such that terminal B1 is the negative terminal and terminal B2 is the positive terminal. If the signal is applied to terminal pair BT02, the upstream transistor pair BT31 is The control is set such that transistor BT33 becomes conductive and transistor BT32 becomes non-conductive. It is controlled by signal S2. On the other hand, the downstream transistor pair BT31 is Control signal S2 such that transistor BT32 is in a conducting state and transistor BT33 is in a non-conducting state. It is controlled by this. In this way, the same Terminals with polarity are connected to each other. Then, the direction of the current flowing from terminal to terminal BT02 is... The system is controlled to charge the battery cells.

[0281] The transformer control circuit BT06 controls the operation of the transformer circuit BT07. The number of BT09 battery cells included in the discharge battery cell group, and the number of batteries included in the recharge battery cell group. Based on the number of cells BT09, a transform signal S3 is generated to control the operation of the transformer circuit BT07. The output is then sent to the transformer circuit BT07.

[0282] Note that the number of BT09 battery cells included in the discharge battery cell group is the same as the number of BT09 battery cells included in the recharge battery cell group. If the number of battery cells exceeds the number of BT09 cells, the charging voltage will be excessively high for the battery cell group. It is necessary to prevent the application of the voltage. Therefore, the transformer control circuit BT06 is designed to prevent the rechargeable battery The transformer circuit BT07 is designed to reduce the discharge voltage (Vdis) to a level that allows the cell group to be charged. It outputs the control transform signal S3.

[0283] Furthermore, the number of BT09 battery cells included in the discharge battery cell group is the same as the number of BT09 battery cells included in the recharge battery cell group. If the number of battery cells is less than or equal to the number of BT09 cells, the charge required to charge the battery cell group will be charged. It is necessary to ensure sufficient voltage. Therefore, the BT06 transformer control circuit is designed to supply excess power to the battery cell group. The transformer circuit BT is designed to increase the discharge voltage (Vdis) within the range where no charging voltage is applied. It outputs a transformer signal S3 to control 07.

[0284] The voltage value that constitutes an excessive charging voltage is the BT09 battery cell used in the BT08 battery unit. The specifications can be determined in consideration of the product specifications, etc. Furthermore, the BT07 transformer circuit can be used for both step-up and step-down. The applied voltage is then applied to the terminal pair BT02 as the charging voltage (Vcha).

[0285] Here, an example of the operation of the transformer control circuit BT06 in this embodiment is shown in Figures 26(A) to (C). This will be explained using the following. Figures 26(A) to (C) show the discharge explained in Figures 23(A) to (C). This section describes an example of the operation of the BT06 transformer control circuit, corresponding to a battery cell group and a rechargeable battery cell group. This is a conceptual diagram for that purpose. Figures 26(A) to (C) illustrate the battery control unit BT41. The battery control unit BT41 has terminal pair BT01 and terminal pair B as described above. T02, switching control circuit BT03, switching circuit BT04, and switching circuit BT0 It consists of 5, the transformer control circuit BT06, and the transformer circuit BT07.

[0286] In the example shown in Figure 26(A), as explained in Figure 21(A), three consecutive high voltages Cells a through c are connected in series with one low-voltage cell d. In this case, see Figure 21(A As explained using ), the switching control circuit BT03 discharges high-voltage cells a to c. The battery cell group is determined, and the low-voltage cell d is determined as the rechargeable battery cell group. Then, the transformer Circuit BT06 is based on the number of battery cells BT09 included in the discharge battery cell group. Based on the ratio of the number of BT09 battery cells included in the rechargeable battery cell group, the discharge voltage (Vdi Calculate the conversion ratio N from s) to the charging voltage (Vcha).

[0287] Note that the number of BT09 battery cells included in the discharge battery cell group is equal to the number of BT09 battery cells included in the recharge battery cell group. If the number of batteries exceeds the number of BT09 cells, the discharge voltage is not transformed and is supplied directly to the BT02 terminal pair. When applied, the battery cell BT09 included in the rechargeable battery cell group is transmitted via the terminal pair BT02. There is a possibility that an excessive voltage may be applied. Therefore, in the case shown in Figure 26(A) This requires that the charging voltage (Vcha) applied to the terminal pair BT02 be reduced to a level lower than the discharge voltage. There is a need for it. Furthermore, in order to charge the battery cell group, the charging voltage is The total voltage of the included BT09 battery cells must be greater than the voltage of the transformer control circuit B. T06 is the number of battery cells BT09 included in the discharge battery cell group, based on the number of charge cells. The conversion ratio N is set to be greater than the ratio of the number of BT09 battery cells included in the battery cell group.

[0288] The voltage transformer control circuit BT06 is based on the number of battery cells BT09 included in the discharge battery cell group. When the number of BT09 battery cells included in the rechargeable battery cell group is set to 1, the conversion ratio N is set to 1 It is preferable to increase it by about 10%. At this time, the charging voltage should be greater than the voltage of the battery cell group. Although it also increases, in reality the charging voltage is equal to the voltage of the battery cell group. However, the voltage transforms The control circuit BT06 adjusts the voltage of the battery cell group to be equal to the charging voltage according to the conversion ratio N. This will supply current to charge the battery cells. This current is supplied to the BT06 transformer control circuit. The set value will be used.

[0289] In the example shown in Figure 26(A), the number of battery cells BT09 included in the discharge battery cell group is 3 Since the number of BT09 battery cells included in the rechargeable battery cell group is 1, the transformer control circuit BT06 calculates the conversion ratio N as a value slightly larger than 1 / 3. Then, the transformer control circuit... BT06 converts the discharge voltage down according to the conversion ratio N and generates a transform signal S3 that converts it into a charging voltage. This is output to the transformer circuit BT07. Then, the transformer circuit BT07 changes the voltage according to the transformer signal S3. The applied charging voltage is then applied to terminal pair BT02. The BT09 battery cell included in the rechargeable battery cell group is charged by the charging voltage.

[0290] Furthermore, in the examples shown in Figures 26(B) and 26(C), the conversion ratio N is the same as in Figure 26(A). This is calculated. In the examples shown in Figures 26(B) and 26(C), the discharge battery cell group is included The number of BT09 battery cells is less than or equal to the number of BT09 battery cells included in the rechargeable battery cell group. Therefore, the conversion ratio N is 1 or greater. Thus, in this case, the transformer control circuit BT06 is discharged It outputs a transform signal S3 that boosts the voltage and converts it to the charging voltage.

[0291] The transformer circuit BT07, based on the transformer signal S3, applies a discharge voltage to the terminal pair BT01. It converts to a charging voltage. Then, the transformer circuit BT07 converts the charging voltage to terminal pair BT0 Apply to 2. Here, the transformer circuit BT07 connects terminal pair BT01 and terminal pair BT02 It is electrically isolated. As a result, the transformer circuit BT07 is at the bottom of the group of discharge battery cells. The absolute voltage of the negative terminal of battery cell BT09 located in the flow, and the lowest-level cell in the rechargeable battery cell group. This prevents short circuits caused by the difference in absolute voltage between the negative terminal of battery cell BT09 located at [location] and [location]. As described above, the transformer circuit BT07 adjusts the combination of the discharge battery cell group based on the transformer signal S3. The discharge voltage, which is the metering voltage, is converted into the charging voltage.

[0292] Furthermore, the BT07 transformer circuit is, for example, an isolated DC (Direct Current)-DC transformer. Converters and the like can be used. In this case, the voltage transformer control circuit BT06 is an isolated DC- The signal that controls the on / off ratio (duty cycle) of the DC converter is the transform signal S3. By outputting, it controls the charging voltage converted by the BT07 transformer circuit.

[0293] Furthermore, isolated DC-DC converters include flyback type, forward type, and RCC ( Ringing Choke Converter system, push-pull system, half-bulb Ridge type and full bridge type exist, but the desired output voltage level depends on the specific design. The appropriate method will be selected.

[0294] Figure 27 shows the configuration of the BT07 transformer circuit using an isolated DC-DC converter. The C-DC converter BT51 includes a switch section BT52 and a transformer section BT53. The BT52 switch unit switches the operation of the isolated DC-DC converter on and off. It is a switch, for example, MOSFET (Metal-Oxide-Semiconduct (Tor Field-Effect Transistor) and bipolar transistors This is achieved using a t-type component. Furthermore, the switch unit BT52 receives an output from the transformer control circuit BT06. Based on the transform signal S3 that controls the on / off ratio, an isolated DC-DC converter is generated. The ON and OFF states of BT51 are periodically switched. Note that the switch unit BT52 is used Various configurations are possible depending on the type of isolated DC-DC converter used. Transformer section BT53 converts the discharge voltage applied from the terminal pair BT01 into a charging voltage. For details, The transformer section BT53 operates in conjunction with the on / off state of the switch section BT52, and its The discharge voltage is converted to a charging voltage according to the on / off ratio. This charging voltage is controlled by the switch unit BT5 In the switching cycle of 2, the longer the time spent in the ON state, the larger the value. On the other hand, charging The voltage is such that the time the switch unit BT52 is ON is shorter during the switching cycle. It becomes much smaller. Note that when using an isolated DC-DC converter, the transformer section BT53 Internally, terminal pair BT01 and terminal pair BT02 can be isolated from each other.

[0295] The processing flow of the energy storage device BT00 in this embodiment will be explained using Figure 28. Figure 28 This is a flowchart showing the processing flow of the BT00 energy storage device.

[0296] First, the energy storage device BT00 acquires the voltage measured for each of the multiple battery cells BT09 ( Step S001). Then, the energy storage device BT00 equalizes the voltage of multiple battery cells BT09. It is determined whether the start condition for the operation is met (step S002). This start condition is, for example, For example, the difference between the maximum and minimum voltage measured for each of the multiple battery cells BT09 is predetermined This can be determined by whether or not it is above a threshold, etc. If this starting condition is not met, (step S0 02:NO), Since the voltage of each battery cell BT09 is balanced, energy storage Device BT00 will not perform the subsequent processing. On the other hand, if the start condition is met (step S 002:YES), the energy storage device BT00 performs the process of equalizing the voltage of each battery cell BT09. In this process, the energy storage device BT00 calculates each cell based on the measured voltage of each cell. It is determined whether battery cell BT09 is a high-voltage cell or a low-voltage cell (step S003). Based on the determination result, the BT00 energy storage device determines the discharge battery cell group and the recharge battery cell group. (Step S004). Furthermore, the energy storage device BT00 uses the determined group of discharge battery cells. The control signal S1 to be set as the connection destination for terminal pair BT01, and the determined group of rechargeable battery cells to terminal A control signal S2 is generated to be set as the connection destination for BT02 (step S005). Energy storage device BT00 receives the generated control signals S1 and S2 from the switching circuit BT04 and the switch The output is sent to the switching circuit BT05. Then, the switching circuit BT04 switches the terminal pairs BT01 and the group of discharge battery cells are connected, and the switching circuit BT05 switches the terminals to BT02 The discharge battery cell group is connected (step S006). Also, the energy storage device BT00 discharges The number of BT09 battery cells included in the battery cell group, and the number of battery cells included in the rechargeable battery cell group Based on the number of BT09s, a transform signal S3 is generated (step S007). Then, The energy storage device BT00, based on the voltage transformation signal S3, determines the discharge voltage applied to the terminal pair BT01. The voltage is converted to a charging voltage and applied to the terminal pair BT02 (step S008). This discharges the voltage. Charge is transferred from the battery cell group to the rechargeable battery cell group.

[0297] Also, in the flowchart in Figure 28, multiple steps are listed in order, but each step The execution order of the commands is not limited to the order in which they are listed.

[0298] As described above, according to this embodiment, when transferring charge from a group of discharged battery cells to a group of rechargeable battery cells, Similar to the capacitor method, charge is temporarily stored from the group of discharge battery cells, and then the charge is stored in the rechargeable battery cells. It does not require a configuration that releases into a group. This improves the charge transfer efficiency per unit time. This can improve the performance. Also, the switching circuits BT04 and BT05 Furthermore, among the discharge battery cell group and the rechargeable battery cell group, the battery cells connected to the transformer circuit are individually selected. It can be switched.

[0299] Furthermore, the transformer circuit BT07 determines the number of battery cells BT09 included in the discharge battery cell group and Based on the number of battery cells BT09 included in the rechargeable battery cell group, the voltage is applied to the terminal pair BT01. The discharge voltage is converted to a charging voltage and applied to the terminal pair BT02. This causes the discharge Regardless of how the BT09 battery cells on the charging and charging sides are selected, charge transfer is achieved without any problems. can.

[0300] Furthermore, OS transistors are used for transistors BT10 and BT13. As a result, leakage occurs from battery cell BT09, which does not belong to the rechargeable battery cell group or the dischargeable battery cell group. The amount of charge can be reduced. This allows the BT09 battery cell, which does not contribute to charging and discharging, to function. This can suppress the decrease in capacitance. Also, OS transistors are different from Si transistors. In comparison, the variation in thermal properties is smaller. As a result, the temperature of the BT09 battery cell rises. Also, normal operation such as switching between conductive and non-conductive states according to control signals S1 and S2. It can be made to do that.

[0301] This embodiment can be implemented in appropriate combination with other embodiments and examples. be.

[0302] (Embodiment 5) <<Other structural examples of secondary batteries>> Figure 29 shows a secondary battery 2100 according to one aspect of the present invention. Figure 29(A) shows secondary battery 21 Figure 29(B) is a perspective view of 00, and Figure 29(C) is a top view of the secondary battery 2100. This is a cross-sectional view of 9(B) along the dashed line G1-G2.

[0303] The secondary battery 2100 shown in Figure 29 has three sides of the outer casing 2107 sealed. Lead 2121 and negative lead 2125, and positive lead 2111, negative lead 2115 and It has a parator 2103. Note that in Figure 29(C), the positive electrode 2111 is shown for clarity. Negative electrode 2115, separator 2103, positive electrode lead 2121, negative electrode lead 2125, o The sealing layer 2120 is shown in part. In addition, some electrodes have two or more current collectors, and the current collector They may be in contact with each other at surfaces where no active material has been formed.

[0304] Here, using Figure 30, we will explain a part of the method for manufacturing the secondary battery 2100 shown in Figure 29. ru.

[0305] First, the negative electrode 2115 is placed on the separator 2103 (Figure 30(A)). At this time, The negative electrode active material layer of electrode 2115 is arranged to overlap with the separator 2103.

[0306] Next, bend the separator 2103 and place it on top of the negative electrode 2115. Next, the positive electrode 2111 is placed on top of the separator 2103 (Figure 30(B)). The positive electrode active material layer of the positive electrode 2111 is superimposed on the separator 2103 and the negative electrode active material layer. Arrange them in such a way. Note that when using electrodes in which an active material layer is formed on one side of the current collector. The positive electrode active material layer of the positive electrode 2111 and the negative electrode active material layer of the negative electrode 2115 are separated by the separator 2103. They are positioned so that they face each other through a gap.

[0307] If the separator 2103 uses a heat-sealable material such as polypropylene, The material is fabricated by heat welding the regions where the electrodes 2103 overlap and then placing the next electrode on top. This can suppress electrode displacement during the process. Specifically, the negative electrode 2115 or the positive electrode 2111 In regions where the separators 2103 are not superimposed on each other, for example, in Figure 30(B) It is preferable to heat-weld the region indicated by region 2103a.

[0308] By repeating this process, as shown in Figure 30(C), the separator 2103 is crossed. The pole 2111 and the negative pole 2115 can be stacked.

[0309] Furthermore, the separator 2103, which has been repeatedly bent in advance, has multiple negative electrodes 2115 and Multiple positive electrodes 2111 may be arranged alternately on either side.

[0310] Next, as shown in Figure 30(C), the separator 2103 has multiple positive electrodes 2111 and multiple It covers the negative electrode 2115.

[0311] Furthermore, as shown in Figure 30(D), there are regions where separators 2103 overlap, for example By heat welding the region 2103b shown in Figure 30(D), multiple positive electrodes 2111 and multiple The negative electrode 2115 is covered with the separator 2103 and secured.

[0312] Furthermore, multiple positive electrodes 2111, multiple negative electrodes 2115, and separators 2103 are bound together with a binding material. You may use it to tie them together.

[0313] In this process, the positive electrode 2111 and the negative electrode 2115 are stacked, so the separator 210 3 is sandwiched between multiple positive electrodes 2111 and multiple negative electrodes 2115 within a single separator 2103. The area is covered and is arranged to cover multiple positive electrodes 2111 and multiple negative electrodes 2115. It has a region.

[0314] In other words, the separator 2103 of the secondary battery 2100 in Figure 29 is partially folded. It is a single separator. In the folded region of separator 2103, multiple positive Electrode 2111 is sandwiched between multiple negative electrodes 2115.

[0315] Figure 31 shows a secondary battery 2200 that is different from the one in Figure 29. Figure 31(A) shows the secondary battery 2200. Figure 31(B) is a perspective view, a top view of the secondary battery 2200. Figure 31(C1) shows the first electrode. Figure 31(C2) shows a cross-sectional view of the second electrode assembly 2131. Figure D) is a cross-sectional view along the dashed line H1-H2 in Figure 31(B). Note that Figure 31(D) Now, to make the diagram clearer, the first electrode assembly 2130, the second electrode assembly 2131 and A section of separator 2103 is shown. In addition, some electrodes have two or more current collectors, and the current collector The bodies may be in contact with each other at surfaces where no active material has been formed.

[0316] The secondary battery 2200 shown in Figure 31 has a positive electrode 2111a and a negative electrode 2115a, and a separator The arrangement of the meter 2103 differs from that of the secondary battery 2100 in Figure 29.

[0317] As shown in Figure 31(D), the secondary battery 2200 comprises a plurality of first electrode assemblies 2130 and It has multiple second electrode assemblies 2131.

[0318] As shown in Figure 31(C1), in the first electrode assembly 2130, positive electrodes are attached to both sides of the positive electrode current collector. Positive electrode 2111a having an active material layer, separator 2103, negative electrode active material on both sides of negative electrode current collector The negative electrode 2115a has a layer, the separator 2103 has a positive electrode active material layer on both sides of the positive electrode current collector. The positive electrodes 2111a are stacked in this order. Also, as shown in Figure 31(C2), the second In the electrode assembly 2131, the negative electrode 2115a has a negative electrode active material layer on both sides of the negative electrode current collector. Separator 2103, positive electrode 2111a having positive electrode active material layers on both sides of the positive electrode current collector, separator -2103 and the negative electrode 2115a, which has negative electrode active material layers on both sides of the negative electrode current collector, are stacked in this order. It is being done.

[0319] Furthermore, as shown in Figure 31(D), there are multiple first electrode assemblies 2130 and multiple second The electrode assembly 2131 is covered by a wound separator 2103.

[0320] Here, using Figure 32, we will explain a part of the method for manufacturing the secondary battery 2200 shown in Figure 31. ru.

[0321] First, the first electrode assembly 2130 is placed on the separator 2103 (Figure 32(A)).

[0322] Next, the separator 2103 is bent and placed on the first electrode assembly 2130. 03 is placed on top. Next, separators 2103 are placed above and below the first electrode assembly 2130. Then, the two sets of second electrode assemblies 2131 are stacked on top of each other (Figure 32(B)).

[0323] Next, the separator 2103 is wound around the two sets of second electrode assemblies 2131. Furthermore, above and below the two sets of second electrode assemblies 2131, via separators 2103, The first electrode assembly 2130 of the set is stacked on top of each other (Figure 32(C)).

[0324] Next, the separator 2103 is wound around the two sets of first electrode assemblies 2130. (Figure 32(D)).

[0325] In this process, multiple first electrode assemblies 2130 and multiple second electrode assemblies 213 To stack them, these electrode assemblies are connected by a spirally wound separator 2103 It is placed between them.

[0326] Furthermore, the positive electrode 2111a of the outermost first electrode assembly 2130 is positive on the outside. It is preferable not to provide an extremely active material layer.

[0327] Furthermore, in Figures 31(C1) and (C2), the electrode assembly has three electrodes and two separators. Although a configuration is shown, the present invention is not limited to this. A configuration with four or more electrodes and three separators is also possible. A configuration with more than one electrode is also acceptable. By increasing the number of electrodes, the capacity of the secondary battery 2200 can be further increased. It can be raised. Alternatively, it may have a configuration with two electrodes and one separator. When there are fewer poles, a more flexible secondary battery 2200 can be created. Also, see Figure 31(D In this case, the secondary battery 2200 has three sets of the first electrode assembly 2130 and the second electrode assembly 213 Although a configuration with two sets of 1 has been shown, the present invention is not limited to this. A three-dimensional configuration is also possible. By increasing the number of electrode assemblies, the capacity of the secondary battery 2200 can be increased. It can be further improved. Furthermore, a configuration with fewer electrode assemblies is also possible. When the number of polarity assemblies is small, a more flexible secondary battery 2200 can be produced.

[0328] The arrangement of the positive electrode 2111 and the negative electrode 2115 of the secondary battery 2200, and the separator 2103 Aside from the arrangement, you can refer to the description in Figure 29.

[0329] This embodiment can be implemented in appropriate combination with other embodiments. [Examples]

[0330] In this embodiment, a lithium-containing material according to one aspect of the present invention, prepared by the method shown in Embodiment 1, is used. Let's explain about compound phosphates.

[0331] First, prepare LiOH·H2O and FeCl so that the molar ratio of Li:Fe:P = 2:1:1. 2·4H2O and NH4H2PO4 were weighed separately. Specifically, LiOH·H2 1.6784g of O, 3.9758g of FeCl2·4H2O, and NH4H2PO4 2.3014g was weighed out separately.

[0332] Next, add LiOH·H2O and FeCl2·4 to 30 ml of pure water that has been bubbling with nitrogen for 30 minutes. H2O and NH4H2PO4 are dissolved, respectively, to obtain a solution containing Li, a solution containing P, and A solution containing Fe was formed.

[0333] Next, under an air atmosphere, the solution containing Li and the solution containing P are mixed while stirring. A combined solution C was formed.

[0334] Next, under an atmospheric environment, while stirring the mixture C, add the Fe-containing solution dropwise in small amounts, and then nitrate. To form mixture D, 10 ml of pure water that had been bubbling for 30 minutes was added.

[0335] Next, the mixture D is placed in an autoclave apparatus having a fluororesin inner cylinder and heated at 150°C for 19 minutes. The sample was heated for a specified time. The pressure inside the inner cylinder during heating was between 0.2 MPa and 0.4 MPa. After heating, the inner cylinder was cooled, and the compound inside the inner cylinder was filtered and washed with water. Autoclave apparatus We used the MS200-C mini reactor manufactured by OM Labtec.

[0336] Next, the mixture B was dried in a vacuum atmosphere at 60°C for 2 hours, and then collected.

[0337] Next, compound B was observed using a scanning electron microscope (SEM). The SEM image is shown in Figure 33. The thium-containing composite phosphate has two plate-like structures, and between the two plate-like structures is a prismatic structure It was confirmed that the structure had the following characteristics, and that there was a gap between the two plate-like structures. For observation, a Hitachi High-Technologies Corporation scanning electron microscope SU8030 was used, with a magnification of 3. It was observed at a magnification of 0,000.

[0338] Next, composite material B is cross-sectioned using FIB (Focused Ion Beam), and composite material B The cross-section was observed using a scanning electron microscope (SEM). The SEM image is shown in Figure 34. Cross-sectional processing using a fiber-infiltrated beam (FIB) and SEM observation. By repeating this process, three-dimensional information about the structure can be obtained. This type of observation method is called Slice a This is called Slice and View. Figures 34(A) through 34(F) show Slice and View. These are images obtained with ew, and the particles shown by the dashed lines in Figures 34(A) to 34(F) are the same particles. This shows that the lithium-containing complex phosphate has two plate-like structures, and the two plate-like structures It was confirmed that there was a prismatic structure between the two plate-like structures, and that there was a gap between them. Oh, for FIB processing, we use the FEI HELIOS NANOLAB650 system, and for SEM observation. A HELIOS NANOLAB650 instrument manufactured by FEI was used for this purpose.

[0339] Next, electron diffraction (XRD) measurements were performed on compound B. The XRD spectrum is shown in Figure 35. Figure 35 shows the diffraction angle 2θ [deg.] on the horizontal axis and the diffracted X-ray intensity (in arbitrary units) on the vertical axis. Take the following. Figure 35 shows the compound B at the top and the inorganic crystal structure database at the bottom. LiFePO4 (Crystal Structure Database: ICSD) This indicates (ICSD Code 92198), and the peak position is almost identical. It was confirmed that compound B is a crystalline form of lithium iron phosphate with an olivine-type structure. For XRD measurements, a Bruker AXS D8 ADVANCE X-ray diffractometer was used. A CuKα ray with a wavelength of 0.15418 nm was used as the radiation source.

[0340] Next, the particle size of compound B was measured. The particle size histogram is shown in Figure 36. The horizontal axis represents particle size [μm], and the vertical axis represents volume-based frequency [%]. Distribution on the small particle size side. The first part of the distribution can be considered as primary particles, and the second part of the distribution on the larger particle diameter side can be considered as aggregates (secondary particles). The frequency was 0.68 μm. The particle size was measured using a laser diffraction particle size analyzer manufactured by Shimadzu Corporation. Using the SALD-2200 fabric measuring device, in the particle size range of 0.03 μm to 1000 μm, Measurements were taken at intervals divided into 51 segments on a multi-scale basis.

[0341] As described above, in this embodiment, the lithium-containing complex phosphate according to one aspect of the present invention The particles were synthesized and their shape and other characteristics were confirmed. [Explanation of Symbols]

[0342] 115 Sealing layer 118 Joint 119 Inlet 200 structures 202 Structure 204 Structure 281 Tab Area 282 Tab Area 300 Secondary battery 301 Positive electrode can 302 Negative electrode can 303 Gasket 304 Positive electrode 305 Positive electrode current collector 306 Positive electrode active material layer 307 Negative electrode 308 Negative electrode current collector 309 Negative electrode active material layer 310 Separator 400 Secondary battery 402 Positive electrode 404 Negative electrode 406 Electrolyte 408 Separator 500 secondary battery 501 Positive electrode current collector 502 Positive electrode active material layer 503 Positive electrode 504 Negative electrode current collector 505 Negative electrode active material layer 506 negative electrode 507 Separator 508 Electrolyte 509 Exterior 510 Positive Lead 511 Negative lead 512 Joint 513 Curved section 514 Joint 518 Joint 600 Secondary battery 601 Positive Cap 602 Battery Can 603 Positive terminal 604 Positive electrode 605 Separator 606 negative electrode 607 Negative terminal 608 Insulating board 609 Insulating board 610 Gasket 611 PTC element 612 Safety valve mechanism 900 Circuit Boards 910 Labels 911 terminal 912 Circuit 913 Secondary battery 914 Antenna 915 Antenna 916 layers 917 layers 918 Antenna 919 terminal 920 Display device 921 Sensor 922 terminals 930 cabinets 930a enclosure 930b enclosure 931 negative electrode 932 Positive electrode 933 Separator 950 Wound body 951 terminal 952 terminals 1700 curved surface 1701 Plane 1702 Curve 1703 Radius of curvature 1704 Center of curvature 1800 Center of curvature 1801 film 1802 radius of curvature 1803 film 1804 Radius of curvature 1805 Electrodes, electrolytes, etc. 2100 secondary battery 2103 Separator 2103a area 2103b area 2107 Exterior 2111 Positive electrode 2111a positive electrode 2115 Negative electrode 2115a negative electrode 2120 Sealing layer 2121 Positive lead 2125 Negative lead 2130 First electrode assembly 2131 Second electrode assembly 2200 secondary battery 7100 Portable Display Device 7101 enclosure 7102 Display section 7103 Operation Buttons 7104 Energy storage device 7400 mobile phones 7401 enclosure 7402 Display section 7403 Operation Buttons 7404 External connection port 7405 Speaker 7406 Microphone 7407 Energy storage device 8021 Charging device 8022 Cable 8100 Automobile 8101 Headlight 8200 automobiles S1 Control signal S2 control signal S3 Transformed signal BT00 Power storage device BT01 terminal pair BT02 terminal pair BT03 Switching Control Circuit BT04 Switching Circuit BT05 Switching Circuit BT06 Transformer Control Circuit BT07 Transformer Circuit BT08 battery part BT09 battery cell BT10 Transistor BT11 bus BT12 bus BT13 Transistor BT14 Current Control Switch BT15 bus BT16 bus BT17 Switch vs BT18 Switch vs BT21 Transistor Pair BT22 Transistor BT23 Transistor BT24 bus BT25 bus BT31 transistor pair BT32 Transistor BT33 Transistor BT34 bus BT35 bus BT41 Battery Control Unit BT51 Isolated DC-DC Converter BT52 Switch Section BT53 Transformer Section S001 Step S002 Step S003 Step S004 Step S005 Step S006 Step S007 Step S008 Step S201a Step S201b Step S201c Step S203a Step S203b Step S203c Step S205 Step S207 Step S209 Step

Claims

1. It has a positive electrode having a tab region and a positive electrode lead electrically connected to the tab region, The tab region has a curved portion, The positive electrode comprises a positive electrode active material layer and a positive electrode current collector. The positive electrode active material layer has a positive electrode active material, The positive electrode active material comprises a plate-shaped first structure, a plate-shaped second structure, and a third structure located between the first structure and the second structure. The third structure is roughly prismatic in shape, A secondary battery in which an air gap is located between the first structure and the second structure.

2. It has a positive electrode having a tab region and a positive electrode lead electrically connected to the tab region, The tab region has a curved portion, The positive electrode comprises a positive electrode active material layer and a positive electrode current collector. The positive electrode active material layer has a positive electrode active material, The positive electrode active material comprises a plate-shaped first structure, a plate-shaped second structure, and a plurality of third structures located between the first structure and the second structure. The aforementioned plurality of third structures are all roughly prismatic in shape, A secondary battery in which an air gap is located between the first structure and the second structure.

3. In claim 1 or claim 2, The first structure described above has a first surface, a second surface, and other surfaces, The first surface has a larger area than the other surfaces. The second surface has a larger area than the other surfaces, and is a secondary battery.

4. In claim 3, A secondary battery in which the first surface and the second surface do not share a common edge.

5. In claim 3 or claim 4, The first surface is roughly n-sided (where n is a natural number greater than or equal to 5), A secondary battery in which at least one of the n interior angles of the first surface is 100° or less.

6. In any one of claims 1 to 5, The positive electrode active material comprises lithium, a metal, phosphorus, and oxygen. A secondary battery wherein the aforementioned metal is one or more selected from iron, manganese, cobalt, and nickel.

7. In any one of claims 1 to 6, The positive electrode active material comprises lithium, iron, phosphorus, and oxygen in a secondary battery.

8. In any one of claims 1 to 7, The positive electrode active material is lithium iron phosphate, and the secondary battery is otherwise.

9. A secondary battery according to any one of claims 1 to 8, A battery control unit having a control circuit.

10. A secondary battery according to any one of claims 1 to 8, An electronic device having a power switch.

11. A secondary battery according to any one of claims 1 to 8, An electronic device having a display device.

12. A secondary battery according to any one of claims 1 to 8, It has input / output terminals, The aforementioned input / output terminal is an electronic device having the function of performing wireless communication.

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