Battery

Abstract

To provide a battery in which contact between foreign matter that has entered the battery case and the positive electrode plate is suppressed. [Solution] The positive electrode plate 100 constituting the electrode body 20 of the battery 1 has a positive electrode current collector foil 101 and a positive electrode composite layer 102 formed on the surface of the positive electrode current collector foil 101. The positive electrode current collector foil 101 has a positive electrode body portion 110 and a positive electrode tab 120 that protrudes from a positive electrode specific end portion 111 of the positive electrode body portion 110. The positive electrode body portion 110 has a composite region 115 where the positive electrode composite layer 102 is formed and is spaced apart from the positive electrode specific end portion 111, and an insulating region 116 where an insulating layer 130 having insulating properties is formed and is located between the positive electrode specific end portion 111 and the composite region 115. At least a portion of the insulating layer 130 between the positive electrode specific end portion 111 and the composite region 115 is thicker than the positive electrode composite layer 102. Furthermore, the porosity of the insulating layer 130 is higher than the porosity of the positive electrode composite layer 102.

Description

Technical Field

[0001] The disclosed technology relates to a battery having an electrode body formed by laminating a positive electrode plate and a negative electrode plate via a separator.

Background Art

[0002] Generally, a battery houses an electrode body formed by laminating a positive electrode plate, a negative electrode plate, and a separator. Further, a composite layer containing an active material is formed on the positive electrode plate and the negative electrode plate. For example, Patent Document 1 describes a battery including an electrode group which is an electrode body including a sheet-shaped positive electrode and a negative electrode, and accommodating the electrode group and an electrolytic solution in a battery case.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, foreign matter may enter the battery case during the manufacturing stage. Specifically, for example, the foreign matter may be contained in the electrolytic solution. And, for example, it is preferable that contact between the foreign matter mixed into the battery case and the positive electrode plate is suppressed. For example, a metallic foreign matter that contacts the composite layer of the positive electrode plate may dissolve according to charge and discharge of the battery, and may further precipitate in the battery case. And depending on the position and degree of the precipitation, there is a possibility of degrading the quality of the battery.

[0005] The disclosed technology aims to provide a battery in which contact between foreign matter mixed into the battery case and the positive electrode plate is suppressed.

Means for Solving the Problems

[0006] One aspect of the disclosed technology is a battery comprising an electrode body formed by laminating a positive electrode plate and a negative electrode plate with a separator in between, a battery case for housing the electrode body and an electrolyte, and a positive electrode current collector and a negative electrode current collector connected to the electrode body, wherein the positive electrode plate has a current collector foil and an asphalt layer formed on the surface of the current collector foil and containing at least an active material, the current collector foil has a main body and a positive electrode tab which is provided protruding from a specific end of the end of the main body and is connected to the positive electrode current collector, the main body has an asphalt region provided at a distance from the specific end and having an asphalt layer formed on its surface, and an insulating region located between the specific end and the asphalt region and having an insulating layer with insulating properties formed on its surface, at least a portion of the insulating layer from the specific end side to the asphalt region side is thicker than the asphalt layer, and the porosity of the insulating layer is higher than the porosity of the asphalt layer.

[0007] In the battery according to the above embodiment, the insulating layer located on a specific end is thicker than the composite layer of the positive electrode plate. Therefore, even if foreign matter is present in the battery case, it is prevented from passing through the insulating layer and entering the inside of the electrode body. As a result, contact between foreign matter mixed into the battery case and the positive electrode plate is suppressed. [Effects of the Invention]

[0008] According to the disclosed technology, a battery is provided in which contact between foreign matter that has entered the battery case and the positive electrode plate is suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of the battery according to an embodiment. [Figure 2] This is a perspective view of an electrode body according to an embodiment. [Figure 3] This figure shows the positive electrode plate, negative electrode plate, and separator that constitute the electrode body according to the embodiment. [Figure 4] This is an enlarged cross-sectional view of the upper end of the electrode body relating to the insulating layer of the first example in the embodiment. [Figure 5]This is an enlarged cross-sectional view of the upper end of the electrode body relating to the insulating layer of the second example in the embodiment. [Figure 6] This is an enlarged cross-sectional view of the upper end of the electrode body relating to the insulating layer of the third example in the embodiment. [Figure 7] This figure shows an example in which an adhesive layer is provided to bond the insulating layer and the separator. [Figure 8] This diagram illustrates the relationship between the thickness of the electrode body and the width of the battery case. [Modes for carrying out the invention]

[0010] The embodiments of the disclosed technology will be described in detail below with reference to the attached drawings.

[0011] Figure 1 shows the battery 1 according to this embodiment. In Figure 1, the X direction extends horizontally and the Z direction extends vertically. The depth direction in Figure 1 is the Y direction. In this embodiment, the battery 1 is a lithium-ion secondary battery. The battery 1 has an electrode body 20 housed inside a battery case 10. The electrode body 20 is composed of a positive electrode plate 100, a negative electrode plate 200, and a separator 30 stacked together.

[0012] The battery case 10 consists of a battery case body 11 and a lid 12. An opening is formed at the top of the battery case body 11 for housing the electrode body 20 inside the battery case body 11, and this opening is closed by the lid 12. An electrolyte 40 is also housed inside the battery case 10.

[0013] The battery case 10 in this embodiment has a flat, rectangular shape overall. Positive terminals 2 and negative terminals 3 are provided near both ends in the longitudinal direction of the lid 12. A positive current collector 4 is provided on the inside side of the battery case 10 of the positive terminal 2. The positive current collector 4 is connected to the positive terminal 2. The positive current collector 4 is also connected to the positive tab 120 inside the battery case 10. In this way, the positive current collector 4 connects the positive terminal 2 to the positive tab 120 of the positive plate 100.

[0014] A negative electrode current collector 5 is provided on the inside of the battery case 10 at the negative electrode terminal 3. The negative electrode current collector 5 is connected to the negative electrode terminal 3. Furthermore, the negative electrode current collector 5 is connected to the negative electrode tab 220 inside the battery case 10. In this way, the negative electrode current collector 5 connects the negative electrode terminal 3 to the negative electrode tab 220 of the negative electrode plate 200. The connection between the positive electrode current collector 4 and the positive electrode tab 120, and the connection between the negative electrode current collector 5 and the negative electrode tab 220 can be made, for example, by welding. The battery 1 can then be charged or discharged via the positive electrode terminal 2 and the negative electrode terminal 3.

[0015] The lid 12 is provided with an injection port 13. The injection port 13 is a hole for injecting electrolyte 40 into the battery case 10. The injection port 13 is sealed by a sealing member 14. The sealing member 14 is attached after the electrolyte 40 has been injected into the battery case 10 through the injection port 13. The electrolyte 40 injected into the battery case 10 is mainly present inside the electrode body 20, at the bottom of the battery case 10, etc.

[0016] Figure 2 is a perspective view of the electrode body 20. The electrode body 20 is composed of stacked sheets of positive electrode plate 100, negative electrode plate 200, and separator 30. The electrode body 20 has a stacked portion 21. The stacked portion 21 is the part in which the positive electrode plate 100 and negative electrode plate 200 are stacked with the separator 30 sandwiched between them. In this embodiment, both the positive electrode tab 120 and the negative electrode tab 220 protrude from the end of the electrode body 20. In this embodiment, both the positive electrode tab 120 and the negative electrode tab 220 are provided to protrude from the upper end 22 of the electrode body 20. As shown in Figure 1, the upper end 22 of the electrode body 20 faces the lid 12 of the battery case 10. In other words, the lid 12 of the battery case 10 is the tab side wall portion that constitutes the wall portion on the side of the electrode body 20 where the positive electrode tab 120 protrudes.

[0017] FIG. 3 is a diagram showing the positive electrode plate 100, the negative electrode plate 200, and the separator 30 that constitute the electrode body 20. In FIG. 3, the positive electrode plate 100, the negative electrode plate 200, and the separator 30 in the electrode body 20 are shown separated in the thickness direction.

[0018] The positive electrode plate 100 has a positive electrode current collector foil 101 and a positive electrode composite layer 102 formed on the surface of the positive electrode current collector foil 101. As the positive electrode current collector foil 101, an aluminum foil can be used. The positive electrode composite layer 102 is composed of a material containing at least a positive electrode active material. The positive electrode active material is a material that contributes to charging and discharging, and in a lithium-ion secondary battery, it stores and releases lithium ions. In addition to the positive electrode active material, materials such as a binder are appropriately contained in the positive electrode composite layer 102. The binder is a material that binds the materials constituting the positive electrode composite layer 102 to the surface of the positive electrode current collector foil 101.

[0019] The positive electrode current collector foil 101 has a positive electrode main body portion 110 and a positive electrode tab 120. The positive electrode main body portion 110 is a portion that constitutes the laminated portion 21 of the electrode body 20. The positive electrode tab 120 is provided so as to protrude from a positive electrode specific end portion 111 which is one of the end portions of the positive electrode main body portion 110. In the present embodiment, the positive electrode specific end portion 111 is the upper end of the positive electrode main body portion 110. The positive electrode tab 120 of the present embodiment protrudes in the Z direction from the positive electrode specific end portion 111.

[0020] The positive electrode main body portion 110 is provided with a composite region 115 having a positive electrode composite layer 102 formed on its surface and an insulating region 116 having an insulating layer 130 formed on its surface. The composite region 115 is provided at an interval from the positive electrode specific end portion 111. The insulating region 116 is a strip-shaped region extending in the X direction along the positive electrode specific end portion 111. That is, the insulating region 116 is located between the positive electrode specific end portion 111 and the composite region 115. Note that neither the positive electrode composite layer 102 nor the insulating layer 130 is formed on the surface of the positive electrode tab 120 of the present embodiment.

[0021] The insulating layer 130 is made of an insulating material. The insulating layer 130 has a higher porosity than the positive electrode composite layer 102. The porosity of the insulating layer 130 and the positive electrode composite layer 102 can be obtained, for example, by cutting the insulating layer 130 and the positive electrode composite layer 102 and observing the respective cut surfaces with a scanning electron microscope (SEM). Alternatively, the porosity of the insulating layer 130 and the positive electrode composite layer 102 can also be obtained by the mercury intrusion method.

[0022] The insulating layer 130 in this embodiment is constructed by bonding insulating particles to it. Examples of insulating particles include powders of alumina (Al2O3), boehmite (Al2O3·H2O), titania (TiO2), and magnesia (MgO). Examples of binders used to bond the insulating particles include polyvinylidene fluoride (PVdF), styrene-butadiene rubber (SBR), and polyacrylates.

[0023] The negative electrode plate 200 has a negative electrode current collector foil 201 and a negative electrode composite material layer 202 formed on the surface of the negative electrode current collector foil 201. In this embodiment, the negative electrode current collector foil 201 is copper foil. The negative electrode composite material layer 202 is composed of a material containing at least a negative electrode active material, and further contains materials such as binders as appropriate.

[0024] The negative electrode current collector foil 201 has a negative electrode body portion 210 and a negative electrode tab 220. The negative electrode body portion 210 is the part that constitutes the laminated portion 21 of the electrode body 20. The negative electrode tab 220 is provided protruding from one of the ends of the negative electrode body portion 210, which is a specific negative electrode end portion 211. In this embodiment, the specific negative electrode end portion 211 is the upper end of the negative electrode body portion 210. In this embodiment, the negative electrode tab 220 protrudes in the Z direction from the specific negative electrode end portion 211.

[0025] The negative electrode body portion 210 has a negative electrode composite material layer 202 formed over its entire surface. In other words, the negative electrode body portion 210 has the negative electrode composite material layer 202 formed from the specific negative electrode end portion 211 to the end opposite to the specific negative electrode end portion 211. The negative electrode tab 220 does not have a negative electrode composite material layer 202 formed on its surface. The back sides of the positive electrode plate 100 and the negative electrode plate 200, which are not shown in Figure 3, are the same as the front sides shown in Figure 3.

[0026] The separator 30 is a porous insulating resin film. The electrolyte 40 is impregnated into the porous separator 30 from the ends of the electrode body 20. As a result, the electrolyte 40 is contained inside the electrode body 20. Figure 3 also shows the separator specific end 31, which corresponds to the positive electrode specific end 111 and the negative electrode specific end 211 of the separator 30.

[0027] The positive electrode plate 100, negative electrode plate 200, and separator 30 in the electrode body 20 are stacked in the order shown in Figure 3. That is, the positive electrode plate 100 and negative electrode plate 200 in the electrode body 20 are stacked with the separator 30 in between. Furthermore, the positive electrode tab 120 and the negative electrode tab 220 are provided at different positions in the X direction. As a result, the positive electrode tab 120 and the negative electrode tab 220 in the electrode body 20 protrude at different positions in the X direction, as shown in Figure 2.

[0028] Figure 4 is an enlarged cross-sectional view of the electrode body 20 at its upper end 22. Figure 4 shows a cross-section at position AA as shown in Figure 1. Figure 4 also shows two positive electrode plates 100 and negative electrode plates 200, and a separator 30 sandwiched between them. The insulating layer 130 shown in Figure 4 has a uniform thickness from the positive electrode specific end 111 side to the positive electrode composite layer 102 side. The thickness of the insulating layer 130 is greater than that of the positive electrode composite layer 102. Therefore, the insulating layer 130 is pressed more firmly against the separator 30 than the positive electrode composite layer 102. This prevents the formation of a gap between the insulating layer 130 and the separator 30.

[0029] In this embodiment of battery 1, the absence of a gap between the insulating layer 130 and the separator 30 prevents foreign matter from entering the space between the positive electrode plate 100 and the separator 30 from the positive electrode specific end 111 side, even if foreign matter is mixed into the battery case 10. In other words, contact between foreign matter and the positive electrode composite layer 102 of the positive electrode plate 100 is prevented. Therefore, the dissolution of foreign matter during charging and discharging of battery 1 is also prevented.

[0030] In this embodiment, the insulating layer 130 is not formed on the surface of the positive electrode composite layer 102 that faces the negative electrode plate 200. If the insulating layer 130 covers the surface of the positive electrode composite layer 102 that faces the negative electrode plate 200, the intercalation and release of lithium ions will not occur smoothly in the positive electrode composite layer 102 covered by the insulating layer 130. Therefore, in this embodiment, the absence of the insulating layer 130 on the surface of the positive electrode composite layer 102 that faces the negative electrode plate 200 prevents a decrease in the volumetric energy density of the battery 1.

[0031] Next, the manufacturing method of the battery 1 will be described. The battery 1 can be constructed by assembling a lid 12 with a positive electrode terminal 2, a negative electrode terminal 3, a positive electrode current collector 4, a negative electrode current collector 5, and an electrode body 20, and then housing the electrode body 20 in this lid 12 inside the battery case body 11. Subsequently, an electrolyte 40 is injected through the inlet 13 of the lid 12, and after the electrolyte 40 has been injected, the inlet 13 is sealed with a sealing member 14. The electrode body 20 can be constructed by laminating a positive electrode plate 100, a negative electrode plate 200, and a separator 30. The positive electrode plate 100 can be manufactured by forming a positive electrode composite layer 102 and an insulating layer 130 in the composite material region 115 and insulating region 116 of the positive electrode current collector foil 101, respectively. The positive electrode composite layer 102 and the insulating layer 130 can be formed in this order. The negative electrode plate 200 can be manufactured by forming a negative electrode composite layer 202 on the negative electrode body portion 210 of the negative electrode current collector foil 201.

[0032] As mentioned above, in the positive electrode plate 100 of this battery 1, the insulating layer 130 has a higher porosity than the positive electrode composite layer 102. Therefore, the electrolyte 40 can pass through the insulating layer 130 more easily than the positive electrode composite layer 102. In other words, the insulating layer 130 does not hinder the electrolyte 40 injected into the battery case 10 from entering the inside of the electrode body 20 from the positive electrode specific end 111 side, compared to the positive electrode composite layer 102. Therefore, the time it takes for the electrolyte 40 injected into the battery case 10 to sufficiently penetrate the inside of the electrode body 20 is not prolonged by the presence of the insulating layer 130. In other words, battery 1 has high productivity.

[0033] Furthermore, in battery 1, the injection port 13 is provided on the lid 12 on the side of the electrode body 20 where the positive electrode tab 120 protrudes. In battery 1, where the battery case 10 has an injection port 13, the electrolyte 40 is generally injected with the lid 12, which is the wall portion where the injection port 13 is provided, facing upwards. As a result, the electrolyte 40 injected from the injection port 13 is supplied to the upper end 22 of the electrode body 20. The positive electrode plate 100 has an insulating layer 130 on the positive electrode specific end 111 side, which is the upper end 22 side of the electrode body 20. Therefore, battery 1 is able to more effectively suppress foreign matter contained in the injected electrolyte 40 from getting between the positive electrode plate 100 and the separator 30, even if foreign matter is present in the electrolyte 40.

[0034] Furthermore, the average particle size of the insulating particles forming the insulating layer 130 is preferably larger than the average particle size of the positive electrode active material particles contained in the positive electrode composite layer 102. The insulating layer 130 tends to have a higher porosity as the insulating particles with a larger average particle size are used. Therefore, by using insulating particles with a larger average particle size than the positive electrode active material in the positive electrode composite layer 102, an insulating layer 130 with a higher porosity than the positive electrode composite layer 102 can be easily formed. In this embodiment, the average particle size is the median diameter, which is the particle size at 50% of the cumulative value in the volume-based particle size distribution obtained by laser diffraction-scattering.

[0035] Furthermore, the insulating layer 130 provided in the insulating region 116 of the positive electrode plate 100 may be in the form shown in Figures 5 and 6. Figures 5 and 6 show two positive electrode plates 100 and a negative electrode plate 200, and a separator 30 sandwiched between them, respectively.

[0036] The insulating layer 130 shown in Figure 5 has an inclined surface 131. The inclined surface 131 of the insulating layer 130 is the surface on the positive electrode specific end 111 side. The inclined surface 131 is inclined in a direction away from the positive electrode current collector foil 101 the further it is from the positive electrode specific end 111. The insulating layer 130 in Figure 5 can guide foreign matter 190 that has moved from the positive electrode specific end 111 side toward the space between the positive electrode plate 100 and the separator 30 toward the separator 30 side, rather than toward the positive electrode current collector foil 101 side. This prevents, for example, foreign matter 190 from coming into contact with the positive electrode current collector foil 101 near the base of the positive electrode tab 120. In other words, it prevents foreign matter 190 from coming into contact with the positive electrode current collector foil 101 and dissolving. Note that the insulating layer 130 shown in Figure 5 is thicker than the positive electrode composite layer 102 toward the positive electrode composite layer 102 side of the inclined surface 131. Therefore, it is possible to effectively prevent foreign matter 190 from entering the space between the positive electrode composite layer 102 and the separator 30.

[0037] The insulating layer 130 shown in Figure 6 has a first part 135 located on the positive electrode specific end 111 side and a second part 136 located on the positive electrode composite layer 102 side of the first part 135. In other words, the first part 135 constitutes the end of the insulating layer 130 on the positive electrode specific end 111 side. The thickness of the first part 135 is 30 μm or less. That is, the thickness of the end face 137 of the first part 135 on the positive electrode specific end 111 side is 30 μm or less. The particle size of foreign matter 190 that enters the battery case 10 tends to be larger than 30 μm. For this reason, foreign matter 190 is less likely to remain on the end face 137 of the first part 135. This makes it possible to suppress, for example, foreign matter 190 from coming into contact with the positive electrode current collector foil 101 near the base of the positive electrode tab 120. In other words, it is possible to prevent foreign matter 190 from coming into contact with the positive electrode current collector foil 101 and dissolving. Note that the insulating layer 130 shown in Figure 6 is thicker than the positive electrode composite layer 102 in the second part 136 which is on the positive electrode composite layer 102 side than the first part 135. Therefore, it is possible to appropriately prevent foreign matter 190 from entering between the positive electrode composite layer 102 and the separator 30.

[0038] Figure 7 also shows an example in which the insulating layer 130 and the separator 30 are bonded together. The electrode body 20 shown in Figure 7 has an adhesive layer 140 between the insulating layer 130 and the separator 30. The adhesive layer 140 is, for example, a hardened adhesive or adhesive tape. The adhesive layer 140 only needs to be provided on at least one of the insulating layer 130 or the separator 30 when constructing the electrode body 20. This further suppresses the formation of a gap between the insulating layer 130 and the separator 30. Therefore, it is further suppressed that foreign matter 190 passes between the insulating layer 130 and the separator 30 and enters the space between the positive electrode composite layer 102 and the separator 30. The insulating layer 130 shown in Figure 7 is the same as the one described in Figure 4. However, the adhesive layer 140 can also be provided when the insulating layer 130 shown in Figure 5 or Figure 6 is used.

[0039] Figure 8 also shows the electrode body 20 and the battery case 10. Figure 8 shows the thickness 21AL of the electrode body 20 and the spacing 11L of the battery case body 11. The thickness 21AL is the thickness of the insulating laminated portion 21A of the electrode body 20, where the insulating layer 130 is laminated. As mentioned above, the insulating layer 130 is thicker than the positive electrode composite layer 102. Therefore, the insulating laminated portion 21A is less likely to become thinner even when compressed in the thickness direction compared to other parts of the laminated portion 21. The spacing 11L is the distance between the two wall portions 15 and 16 of the battery case body 11 that sandwich the electrode body 20 in the thickness direction. In this embodiment, the wall portions 15 and 16 of the battery case body 11 are the walls of the battery case 10 and are side walls located opposite each other. In battery 1, it is preferable that the thickness 21AL of the electrode body 20 is 98% or more of the spacing 11L of the battery case body 11. As a result, when the electrode body 20 is housed inside the battery case body 11, the battery case body 11 can appropriately restrain the insulating laminate portion 21A of the electrode body 20 so that it does not bulge in the thickness direction. In other words, it is possible to maintain a state in which a gap large enough for foreign matter to pass through does not form between the insulating layer 130 laminated in the insulating laminate portion 21A and the separator 30. Therefore, contact between the positive electrode composite layer 102 and foreign matter can be suppressed even more appropriately. Note that in the case of an insulating layer 130 with an uneven thickness as shown in Figure 5 or Figure 6, the thickness 21AL of the insulating laminate portion 21A is the thickness of the thickest part of the insulating layer 130 that is laminated. In other words, the thickness 21AL of the insulating laminate portion 21A is the maximum thickness of the insulating laminate portion 21A.

[0040] As described above, the battery 1 according to the above embodiment has a battery case 10 that houses an electrode body 20 and an electrolyte 40. The electrode body 20 is composed of a positive electrode plate 100 and a negative electrode plate 200 stacked with a separator 30 in between. A positive electrode current collector 4 and a negative electrode current collector 5 are connected to the electrode body 20. The positive electrode plate 100 has a positive electrode current collector foil 101 and a positive electrode composite material layer 102. The positive electrode composite material layer 102 is formed on the surface of the positive electrode current collector foil 101 and contains at least positive electrode active material. The positive electrode current collector foil 101 has a positive electrode body portion 110 and a positive electrode tab 120. The positive electrode tab 120 is provided protruding from a positive electrode specific end portion 111 of the positive electrode body portion 110. The positive electrode tab 120 is also the portion of the positive electrode current collector foil 101 that is connected to the positive electrode current collector 4. The positive electrode body portion 110 has a composite material region 115 and an insulating region 116. The composite material region 115 is the region on which the positive electrode composite material layer 102 is formed on the surface. The composite material region 115 is also provided at a distance from the positive electrode specific end 111. The insulating region 116 is the region on which an insulating layer 130 having insulating properties is formed on the surface. The insulating region 116 is also located between the positive electrode specific end 111 and the composite material region 115. At least a portion of the insulating layer 130 between the positive electrode specific end 111 and the composite material region 115 is thicker than the positive electrode composite material layer 102. Furthermore, the porosity of the insulating layer 130 is higher than that of the positive electrode composite material layer 102. For this reason, in battery 1, even if foreign matter is present in the battery case 10, it is suppressed that the foreign matter will pass through the insulating layer 130 and enter the interior of the electrode body 20. As a result, in battery 1, contact between foreign matter mixed into the battery case 10 and the positive electrode plate 100 is suppressed. Furthermore, although the insulating layer 130, which has a higher porosity than the positive electrode composite layer 102 of the positive electrode plate 100, is located at the upper end 22, which is the end of the electrode body 20, it does not prevent the penetration of the electrolyte 40 into the interior of the electrode body 20 from the upper end 22 side. Therefore, battery 1 also suppresses a decrease in productivity.

[0041] The embodiments described above are merely illustrative and do not limit the disclosed technology in any way. Therefore, the disclosed technology can naturally be improved and modified in various ways without departing from its essence.

[0042] For example, the configuration shown in the above embodiment is merely one example. For instance, the electrode body was described as being constructed by stacking a positive electrode plate, a negative electrode plate, and a separator flat. However, the electrode body may also be constructed by stacking the positive electrode plate, negative electrode plate, and separator and winding them together. For example, the ends of the positive electrode tab and the negative electrode tab that protrude from the electrode body do not necessarily have to be the same end. For example, the injection port for injecting the electrolyte into the battery case may be provided on a different wall from the wall on the side of the electrode body where the positive electrode tab protrudes. For example, the battery case may not have an injection port, in which case the electrolyte can be contained into the battery case through the same opening as the electrode body.

[0043] For example, the insulating region where the insulating layer is formed on the positive electrode current collector foil only needs to be between the positive electrode specific end of the positive electrode body and the composite material region, and there may be gaps between the insulating region and the positive electrode specific end, and between the insulating region and the composite material region, or at least one of them. Also, for example, the insulating layer only needs to be thicker than the composite material layer in at least a portion between the positive electrode specific end and the composite material region. That is, for example, the insulating layer may have a portion that is thicker than the positive electrode composite material layer on the positive electrode specific end side, and the insulating layer on the composite material region side may be thinner than the positive electrode composite material layer.

[0044] Furthermore, for example, the insulating layer may be a combination of the configuration described in Figure 5 and the configuration described in Figure 6. Specifically, for example, the insulating layer may have a thickness of 30 μm or less at the end face on the positive electrode specific end side, and may have an inclined surface connected to that end face that is inclined in a direction away from the positive electrode current collector foil as it moves further away from the positive electrode specific end.

[0045] Furthermore, for example, the thickness of the insulating laminate portion, which is the area in the electrode body where the insulating layer is laminated, may be less than 98% of the distance between the two walls in the battery case that sandwich the electrode body in the thickness direction. This is because having an insulating layer that is thicker than the positive electrode composite layer helps to suppress the entry of foreign matter into the electrode body compared to when there is no insulating layer. Also, even if the thickness of the insulating laminate portion of the battery is less than 98% of the distance between the two walls in the battery case that sandwich the electrode body in the thickness direction, the adhesive layer shown in Figure 7 can appropriately suppress the entry of foreign matter into the electrode body.

[0046] Furthermore, for example, the application of the above embodiment is not particularly limited in terms of battery type (such as nickel-metal hydride batteries or lithium-ion batteries). Also, the technology disclosed in the above embodiment can be implemented in various forms, such as battery manufacturing methods.

[0047] Furthermore, the disclosed technology described above includes the following means 1 to means 7. [Means 1] An electrode body is formed by stacking a positive electrode plate and a negative electrode plate with a separator in between, A battery case containing the electrode body and electrolyte, A battery comprising a positive electrode current collector and a negative electrode current collector connected to the electrode body, The positive electrode plate is The current collector foil and the composite layer formed on the surface of the current collector foil, which contains at least an active material, The aforementioned current collector foil is It has a main body and a positive electrode tab that protrudes from a specific end of the main body and is connected to the positive electrode current collector. The main body is, A region of asphalt material provided at a distance from the aforementioned specific end, on which the asphalt material layer is formed on the surface, It has an insulating region located between the specific end and the composite material region, and having an insulating layer having an insulating layer formed on its surface, At least a portion of the insulating layer from the specific end side to the asphalt mixture area side is thicker than the asphalt mixture layer. A battery in which the porosity of the insulating layer is higher than that of the composite layer.

[0048] [Means 2] The battery described in means 1, The aforementioned battery case is A battery in which an injection port for injecting the electrolyte is provided in the tab side wall portion, which is the wall portion on the side of the electrode body on which the positive electrode tab protrudes.

[0049] [Means 3] A battery according to means 1 or means 2, The insulating layer is formed by bonding insulating particles having insulating properties. A battery in which the average particle diameter of the insulating particles is larger than the average particle diameter of the active material particles.

[0050] [Means 4] A battery according to any of the means 1 to means 3, The insulating layer has an inclined surface that slopes away from the current collector foil as it moves further away from the specific end.

[0051] [Means 5] A battery according to any of the means 1 to means 4, A battery in which the thickness of the end of the insulating layer on the specific end side is 30 μm or less.

[0052] [Means 6] A battery according to any of the means 1 to means 5, A battery having an adhesive layer between the insulating layer and the separator to bond them together.

[0053] [Means 7] A battery according to any of the means 1 to means 6, A battery in which the thickness of the insulating laminate portion, which is the area in the electrode body where the insulating layer is laminated, is 98% or more of the distance between the two walls in the battery case that sandwich the electrode body in the thickness direction. [Explanation of Symbols]

[0054] 1:Battery 4: Positive electrode current collector 5: Negative electrode current collector 10: Battery case 11: Battery case body 12: Lid (tab side wall) 13: Inlet 15, 16: Wall part 20: Electrode body 21A: Insulating laminated section 21AL: Thickness 30: Separator 40: Electrolyte 100: Positive plate 101: Positive electrode current collector foil (current collector foil) 102: Positive electrode composite material layer (compound material layer) 110: Positive electrode body (body) 111: Positive electrode specific end (specific end) 115: Composite material area 116: Insulated Area 120: Positive Tab 130: Insulating layer 131: Inclined surface 140: Adhesive layer 200: Negative electrode plate

Claims

1. An electrode body is formed by stacking a positive electrode plate and a negative electrode plate with a separator in between, A battery case containing the electrode body and electrolyte, A battery comprising a positive electrode current collector and a negative electrode current collector connected to the electrode body, The positive electrode plate is The current collector foil and the composite layer formed on the surface of the current collector foil, which contains at least an active material, The aforementioned current collector foil is It has a main body and a positive electrode tab that protrudes from a specific end of the main body and is connected to the positive electrode current collector. The main body is, A region of asphalt material provided at a distance from the aforementioned specific end, on which the asphalt material layer is formed on the surface, It has an insulating region located between the specific end and the composite material region, and having an insulating layer having an insulating layer formed on its surface, At least a portion of the insulating layer from the specific end side to the asphalt mixture area side is thicker than the asphalt mixture layer. A battery in which the porosity of the insulating layer is higher than that of the composite layer.

2. The battery according to claim 1, The aforementioned battery case is A battery in which an injection port for injecting the electrolyte is provided in the tab side wall portion, which is the wall portion on the side of the electrode body on which the positive electrode tab protrudes.

3. The battery according to claim 1, The insulating layer is formed by bonding insulating particles having insulating properties. A battery in which the average particle diameter of the insulating particles is larger than the average particle diameter of the active material particles.

4. The battery according to claim 1, The insulating layer has an inclined surface that slopes away from the current collector foil as it moves further away from the specific end.

5. The battery according to claim 1, A battery in which the thickness of the end of the insulating layer on the specific end side is 30 μm or less.

6. The battery according to claim 1, A battery having an adhesive layer between the insulating layer and the separator to bond them together.

7. The battery according to claim 1, A battery in which the thickness of the insulating laminate portion, which is the portion of the electrode body where the insulating layer is laminated, is 98% or more of the distance between the two walls of the battery case that sandwich the electrode body in the thickness direction.

Images