JP5292260B2 - Non-aqueous secondary battery and battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous secondary battery such as a lithium-ion secondary battery, which is free from deterioration of capacity, deterioration of positive electrode material, precipitation of metal lithium, or the like by solving a local potential distribution within a cell by sub-reaction in charging and discharging, and to provide a battery module. <P>SOLUTION: In the nonaqueous secondary battery which includes a positive electrode, a negative electrode and an electrolyte, and charges and discharges electricity by repeating the reaction of releasing or absorbing ions from the positive electrode or negative electrode into the electrolyte, an ion supply source which elutes the same kind of ions as the ions used for the charge and discharge, a mesh electrode contacting a part of a surface of the negative electrode, and a diode disposed to connect the ion supply source to the mesh electrode with the mesh electrode side being + polarity are provided within the electrolyte inside the secondary battery. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a non-aqueous secondary battery, and more particularly, to a high energy density lithium ion secondary battery suitable for use in portable equipment, electric vehicles, power storage, and the like, and a battery module thereof.

  In a lithium ion secondary battery using a carbon material as a negative electrode active material, it is known that a film can be formed on the surface of the negative electrode due to a side reaction accompanying a negative electrode charging reaction at the first charge after the battery is manufactured.

  It is known that this film grows during storage in a relatively high temperature environment and as the negative electrode surface side reaction proceeds with charge / discharge cycles. Since this side reaction is accompanied by lithium ion desorption in the negative electrode, the battery characteristics such as capacity deterioration due to the potential of the positive electrode and the negative electrode shifting to the higher potential side and resistance increase due to the increase in the film thickness of the negative electrode surface film are included. The problem is that it causes deterioration.

  As a conventional technique for solving this problem, for example, Patent Document 1 discloses that lithium is attached to a carbon negative electrode. In the technique disclosed in Patent Document 1, lithium attached to the carbon negative electrode is self-dissolved and ions are released to the carbon negative electrode, so that ions desorbed from the negative electrode by a side reaction are supplemented. Thereby, it is possible to return the negative electrode to the low potential side and suppress the capacity deterioration.

  In Patent Document 2, lithium is arranged as the third electrode inside the battery, an electrode terminal having the third electrode connected to the cell surface is arranged, and the amount of lithium ion desorption from the negative electrode is determined as the third electrode. Judging from the potential difference of the negative electrode, it describes supplying consumed lithium ions. As a result, the negative electrode can be returned to the low potential side to suppress the capacity deterioration.

  Further, Patent Document 3 describes that a potential measuring means is provided between the third electrode and the positive electrode, and automatically supplied lithium ions are supplied when the potential difference is a predetermined value or more.

JP-A-5-234622 JP-A-8-190934 JP 2007-305475 A

  However, the approach of supplying lithium ions as in the prior art is based on the premise that the occurrence of side reactions on the negative electrode surface and the shift of each electrode to the high potential side are uniform within the cell.

  It is known that the side reaction on the negative electrode surface accelerates due to a temperature rise, an increase in the number of charge / discharge cycles, and a large current charge / discharge. As a situation where a plurality of these factors overlap, there is a case where a large lithium ion battery cell is charged and discharged many times with a large current.

  When a lithium ion battery is repeatedly charged and discharged with a large current, the cell generates heat due to Joule heat generation caused by the internal resistance of the battery. The generated heat is dissipated into the air from the outer periphery of the cell, but there is a thermal resistance between the cell center and the outer periphery. It becomes hot. In addition, in the lithium ion secondary battery, since the internal resistance generally decreases due to a temperature rise, the current concentrates in the cell center portion from the cell outer periphery portion.

  Thus, since the cell center is considered to have a higher temperature and a larger current than the cell outer periphery, it can be inferred that the side reaction on the negative electrode surface at the cell center is accelerated from the cell outer periphery.

  Such a local potential distribution in the cell cannot be detected at all from the voltage between the positive electrode and the negative electrode observed from the outside of the cell, and cannot be detected even when the voltage is lithium as the third electrode. It is.

  The object of the present invention is to solve such problems and problems.

  That is, the object of the present invention is to eliminate local potential distribution inside the cell due to side reactions during charge and discharge in a non-aqueous secondary battery such as a lithium ion secondary battery, and to suppress capacity deterioration. The object is to provide a non-aqueous secondary battery and a battery module.

  The present invention relates to a non-aqueous secondary battery that includes a positive electrode, a negative electrode, and an electrolytic solution, and discharges ions from the positive electrode or the negative electrode into the electrolytic solution, or repeatedly charges and discharges. An ion source that elutes ions of the same type as those used for charging / discharging in the electrolyte inside the secondary battery, a mesh electrode that is in contact with part of the negative electrode surface or part of the positive electrode surface, and ion supply A diode is provided in which the source and the mesh electrode are connected and the mesh electrode side is arranged with a positive polarity.

  A resistive element may be used instead of the diode. That is, the ion supply source and the mesh electrode may be connected by a resistance element.

  Further, a transistor in which a negative electrode, an ion supply source, and a mesh electrode are connected and the negative electrode is connected to a gate terminal may be used.

  Here, the positive electrode is one in which an oxide containing lithium is used as a positive electrode active material and is applied to both surfaces of a positive electrode foil that is a current collector. The negative electrode is formed by using a carbon-based material as a negative electrode active material and applied to both surfaces of a negative electrode foil as a current collector. The electrolytic solution is an organic electrolytic solution in which a salt containing lithium is dissolved. The ion supply source is a material containing lithium, and the mesh electrode is preferably in contact with the active material surface of the positive electrode or the negative electrode.

More specifically, examples of the positive electrode material include Li _x CoO ₂ , Li _x NiO ₂ , Li _x Mn ₂ O ₄ , and Li _x FeO ₂ (where x is in the range of 0 to 1), and the negative electrode active material. For example, a carbon-based material such as graphite or coke having a graphite interlayer distance of 0.344 nm or less is preferable because of its excellent charge / discharge reversibility.

As an electrolytic solution, a mixed solvent obtained by adding at least one of ethylene carbonate to dimethoxyethane, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, methyl propionate, and ethyl propionate, and LiClO ₄ and LiPF _{6 are used.} , LiBF ₄ , LiCF ₃ SO _{3 and the} like, and at least one electrolyte is preferably used, and the lithium concentration is preferably in the range of 0.5 to 2.0 mol / l.

  In addition, a sheet-like separator that holds the electrolyte solution is disposed between the positive electrode and the negative electrode, and the positive electrode, the separator, the negative electrode, and the separator are alternately overlapped and wound into a cylindrical shape to form an electrode group. In the battery cell in which is inserted into the cylindrical metal can, it is desirable that the mesh electrode and the ion supply source are arranged near the central axis of the electrode group.

  A plurality of these secondary batteries may be used to form an assembled battery, and the positive and negative electrodes of the assembled battery may be connected in series or in series and parallel to form a battery module.

  According to the present invention, it is possible to provide a non-aqueous secondary battery and a battery module that can suppress capacity deterioration, and it is possible to provide a non-aqueous secondary battery and a battery module that have a long life and increase safety.

1 is a schematic diagram of a lithium ion secondary battery cell in Example 1. FIG. 1 is a cross-sectional view of a lithium ion secondary battery cell in Example 1. FIG. 2 is a functional diagram of a lithium ion secondary battery cell in Example 1. FIG. 4 is a schematic diagram of a lithium ion secondary battery cell in Example 2. FIG. Sectional drawing of the lithium ion secondary battery cell in Example 2. FIG. FIG. 4 is a functional diagram of a lithium ion secondary battery cell in Example 2. 4 is a schematic diagram of a lithium ion secondary battery cell in Example 3. FIG. Sectional drawing of the lithium ion secondary battery cell in Example 3. FIG. FIG. 6 is a functional diagram of a lithium ion secondary battery cell in Example 3. FIG. 6 is a schematic view of a lithium ion secondary battery cell in Example 4. Sectional drawing of the lithium ion secondary battery cell in Example 4. FIG. FIG. 10 is a functional diagram of a lithium ion secondary battery cell in Example 5. The functional diagram of the lithium ion secondary battery cell in Example 6. FIG. FIG. 9 is a functional diagram of a lithium ion secondary battery cell in Example 7. The figure which shows the initial stage charge / discharge state of a lithium ion secondary battery cell. The figure which shows the charging / discharging state of the outer peripheral part after the test of a lithium ion secondary battery cell. The figure which shows a partial electrode investigation position after decomposition | disassembly of a lithium ion secondary battery cell. The figure which shows the charging / discharging characteristic of the center part electrode of a lithium ion secondary battery cell. The figure which shows the charging / discharging characteristic of the intermediate part electrode of a lithium ion secondary battery cell. The figure which shows the charging / discharging characteristic of the outer peripheral part electrode of a lithium ion secondary battery cell. 10 is a schematic diagram of a lithium ion secondary battery module in Example 8. FIG.

  The best mode for carrying out the present invention will be described below.

  FIG. 1 is a schematic view of a lithium ion secondary battery cell according to the present embodiment, FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. 1, and FIG. 3 is a lithium ion secondary battery according to the present embodiment. The figure showing a cell function is shown.

  As shown in FIGS. 1 and 2, an electrode group 101 is inserted into the battery can 100. In the electrode group 101, the positive electrode 200, the negative electrode 300, and the separator 350 are alternately stacked between the positive electrode and the negative electrode and wound into a cylindrical shape.

  A mesh electrode 400 is arranged on the surface of the negative electrode 300 near the center, which is the position farthest from the outer periphery of the cell and where the temperature is highest when the cell generates heat. The supply source 401 is connected by a diode 402 with the mesh electrode 400 as a positive polarity side.

  The ion supply source 401 is the farthest position from the outer periphery of the cell, and is inserted in a gap in the central axis of the electrode group that seems to be the position where the temperature becomes highest when the cell generates heat.

  In addition to these, an electrolytic solution 360 is injected into the battery can 100 and sealed with the positive electrode lid 102 and the gasket 103.

In this embodiment, LiCoO _{2 is} added as a positive electrode active material of the battery, 7 wt% of acetylene black is added as a conductive agent, and 5 wt% of polyvinylidene fluoride (PVDF) is added as a binder, and N-methyl-2-pyrrolidone is added thereto. The mixture was mixed to prepare a positive electrode mixture slurry.

  This positive electrode mixture slurry is applied and dried on both surfaces of a positive electrode foil 201 (see FIG. 3), which is an aluminum foil having a thickness of 25 μm, and then pressed and cut, so that the positive electrode material 202 (see FIG. 3) is formed on both surfaces of the positive electrode foil 201. The positive electrode 200 was obtained by binding.

  Similarly, non-graphitizable carbon was used as the negative electrode active material, 8 wt% of PVDF was added as a binder, and N-methyl-2-pyrrolidone was added thereto and mixed to prepare a slurry of the negative electrode mixture.

  The negative electrode mixture slurry is applied to both surfaces of a negative electrode foil 301 (see FIG. 3), which is a copper foil having a thickness of 10 μm, and pressed and cut to bind the negative electrode material 302 (see FIG. 3) to both surfaces of the negative electrode foil 301. A negative electrode 300 was formed.

  Metal ion is used for the ion supply source 401.

  And with respect to this metallic lithium, the potential of the negative electrode material in this example changes to about 0.1 V during charging and to about 1.2 V during discharging in the normal use range.

  As shown in FIG. 3, the diode 402 has a voltage threshold value of +1 in order to allow a current to flow through the diode 402 only when the negative electrode at the center portion becomes a high potential due to lithium ion desorption due to a side reaction on the negative electrode surface. The one with the characteristic that current passes only when there is a potential difference of .2V or more is used.

  In addition, in order to detect that the negative electrode in the central portion is at a high potential, the mesh electrode 400 is attached only to the surface in the vicinity of the central portion of the negative electrode material 302, and a copper foil having a hole so that lithium ions can pass therethrough. Is used.

  In this embodiment, the threshold value of the diode 402 is 1.2 V. However, depending on the purpose of use of the battery cell, only a narrow charge / discharge range is used, and when the potential change of the negative electrode material 302 can be expected to be small, for example, about 0.6 V A diode having a small threshold may be used. Moreover, you may use metal foils other than copper foil also in a mesh electrode material.

  Here, the result at the time of actually charging / discharging a battery cell with a large current is demonstrated using FIGS. 15-20.

  The battery cell used in the experiment has a diameter of 40 mm, a length of 108 mm, and an electric capacity of 5.5 Ah.

  After charging / discharging the cell at a current of 90 A and charging / discharging time of 90 seconds 3000 times, the cell was disassembled, and the positive electrode and negative electrode at the center, middle and outer periphery of the cell as shown in FIG. 17 were cut out. Thus, the charge / discharge characteristics of the partial electrodes were investigated.

  FIG. 18 shows the charge / discharge characteristics of the center electrode, FIG. 19 shows the charge / discharge characteristics of the intermediate electrode, and FIG. 20 shows the charge / discharge characteristics of the outer peripheral electrode. The horizontal axis is the charge / discharge capacity, and the vertical axis is the voltage or potential. In the figure, the curve indicated by a white circle (◯) is the voltage between the positive electrode and the negative electrode, the white triangle (Δ) is the potential of the positive electrode with respect to lithium inserted as a reference electrode, and the white square (□) is the same. The potential of the negative electrode with respect to lithium is shown.

  Solid diamonds (♦) indicate characteristics when charge / discharge measurement is performed using only the positive electrode and lithium, and filled squares (■) indicate characteristics when charge / discharge is measured using only the negative electrode and lithium.

  According to these figures, the electrode at the center of the cell has a smaller charge / discharge capacity than the electrode at the outer periphery of the cell, and both the positive electrode and the negative electrode have a high potential. This is considered to be a result of acceleration of the side reaction on the negative electrode surface due to the high temperature and current concentration in the center of the cell.

  FIG. 15 shows the initial charge / discharge state of the outer periphery of the cell and the center of the cell. On the other hand, side reactions on the negative electrode surface are accelerated by high temperature and current concentration, and lithium ions are desorbed from the inside of the negative electrode, so that the negative electrode potential at the center of the cell shifts to the high potential side. Here, since the voltage defined from the outside at the time of charging / discharging is a potential difference between the positive electrode and the negative electrode, when the negative electrode is at a high potential, the positive electrode is also shifted to the high potential side. As a result, it can be considered that the center electrode is in a charge / discharge state as shown in FIG.

Such an increase in the potential of the electrode at the center of the cell, in particular the increase in the potential of the positive electrode, is undesirable because it causes deterioration of crystals such as LiCoO ₂ that is the positive electrode active material, such as crystal collapse and oxygen desorption. In addition, the fact that one side of the electrode material on the same electrode foil has a high potential means that the opposite side needs to have a low potential for compensation. Actually, the partial electrode potential of the outer peripheral negative electrode shown in FIG. 20 shows a very low potential, and there is a possibility that metallic lithium is deposited on the negative electrode surface during charging.

  In the battery cell of this example, the diameter was 40 mm and the axial length was 108 mm, but the electric capacity was about 5.0 Ah. In order to obtain an experiment similar to the above-described experiment, the ratio of the current to the electric capacity was adjusted, and charging and discharging with a current 82A and a charging / discharging time of 90 seconds were repeated 3000 times on this cell, and then the cell was disassembled. When the negative electrode at the center and the outer periphery of the cell was cut out and the potential difference between the negative electrode at the center and the outer periphery was measured, the potential difference between the center and the outer periphery of the cell was measured during the negative discharge shown in FIGS. The potential difference was smaller than 0.5V and about 0.2V, and the local potential difference inside the cell could be reduced.

  As described above, in this example, the local potential distribution inside the cell caused by the temperature distribution in the cell due to heat generation during charging and discharging could be eliminated. As a result, it is possible to provide a battery free from capacity deterioration, positive electrode material deterioration, metallic lithium deposition, and the like.

  That is, in a non-aqueous secondary battery such as a lithium ion secondary battery, the local potential distribution inside the cell due to side reactions during charge and discharge is eliminated, and there is no capacity deterioration, cathode material deterioration, metallic lithium deposition, etc. In addition, a battery module can be provided.

  The present embodiment is the same as the first embodiment except for the following points.

  FIG. 4 is a schematic view of a lithium ion secondary battery cell according to the present embodiment, FIG. 5 is a cross-sectional view taken along the line BB ′ of FIG. 4, and FIG. 6 represents a lithium ion secondary battery cell function according to the present embodiment. The figure is shown.

  In the present embodiment, the mesh electrode 400 is disposed on the surface of the negative electrode 300 near the center, which is the position farthest from the outer periphery of the cell and where the temperature is highest when the cell generates heat. In this respect, the mesh electrode 400, the ion supply source 401, and the negative electrode 300 are connected by the transistor 403, although the same as in the first embodiment.

  Here, the mesh electrode 400 is characterized by being connected to the gate terminal of the transistor 403. Further, the transistor 403 is connected to the negative electrode foil 301 in the negative electrode 300.

  With such a configuration, only when the potential of the negative electrode material 302 near the center of the cell detected by the mesh electrode 400 is higher than the negative electrode foil 301 that is the average potential of the negative electrode material 302 of the entire cell, A current flows between the supply source 401 and the negative electrode foil 301, and ions are preferentially supplied from the negative electrode material 302 close to the ion supply source 401.

  Also in this embodiment, the ion supply source 401 uses lithium and is located farthest from the outer periphery of the cell, and is located on the central axis of the electrode group that is considered to be the highest temperature when the cell generates heat. Since it is inserted into a certain gap, it is possible to selectively lower the potential of the portion where the potential change is most likely to occur.

  Also in the battery cell of this example, as in Example 1, the diameter was 40 mm and the axial length was 108 mm, but the electric capacity was about 5.0 Ah. After charging / discharging the cell at a current 82A for 90 seconds with a charge / discharge time of 3000 times, the cell was disassembled, the negative electrode at the center and the outer periphery of the cell was cut out, and the potential difference between the negative electrode at the center and the outer periphery As a result, the potential difference between the central portion and the outer peripheral portion of the cell was about 0.2 V as in Example 1, and the local potential difference inside the cell could be reduced.

  As described above, in this example, the local potential distribution inside the cell caused by the temperature distribution in the cell due to heat generation during charging and discharging could be eliminated. As a result, it is possible to provide a battery free from capacity deterioration, positive electrode material deterioration, metallic lithium deposition, and the like.

  The present embodiment is the same as the first embodiment except for the following points.

  FIG. 7 is a schematic diagram of a lithium ion secondary battery cell according to the present embodiment, FIG. 8 is a cross-sectional view taken along the line CC ′ of FIG. 7, and FIG. 9 is a diagram illustrating a lithium ion secondary battery cell function according to the present embodiment. The figure is shown.

  In this embodiment, the mesh electrode 400 is disposed on the surface of the negative electrode 300 near the center, which is the position farthest from the outer periphery of the cell and where the temperature is highest when the cell generates heat. In the same manner as in the first embodiment, the mesh electrode 400 and the ion supply source 401 are connected by a resistor 404.

  With such a configuration, a larger current is generated between the ion supply source 401 and the mesh electrode 400 as the potential of the negative electrode material 302 near the center of the cell detected by the mesh electrode 400 becomes larger than that of the ion supply source 401. Flows, and ions are preferentially supplied from the negative electrode material 302 close to the ion supply source 401.

  Also in this embodiment, the ion supply source 401 uses lithium and is located at the farthest position from the outer periphery of the cell, and at the central axis of the electrode group that seems to be the position where the temperature becomes highest when the cell generates heat. Since it is inserted in the gap, it is possible to selectively lower the potential of the portion where the most potential change is likely to occur.

  Also in the battery cell of this example, as in Example 1, the diameter was 40 mm and the axial length was 108 mm, but the electric capacity was about 5.0 Ah. After charging / discharging the cell at a current 82A for 90 seconds with a charge / discharge time of 3000 times, the cell was disassembled, the negative electrode at the center and the outer periphery of the cell was cut out, and the potential difference between the negative electrode at the center and the outer periphery As a result, the potential difference between the cell central portion and the outer peripheral portion was about 0.3 V, and the local potential difference inside the cell could be reduced.

  As described above, in this example, the local potential distribution inside the cell caused by the temperature distribution in the cell due to heat generation during charging and discharging could be eliminated. As a result, it is possible to provide a battery free from capacity deterioration, positive electrode material deterioration, metallic lithium deposition, and the like.

  This example is the same as Example 2 except for the following points.

  FIG. 10 is a schematic view of a lithium ion secondary battery cell in this example, and FIG. 11 is a cross-sectional view taken along the line DD ′ of FIG.

  In the present embodiment, the outer shape of the battery can 100 is not cylindrical but rectangular. The electrode material of the positive electrode and the negative electrode is the same as in the first and second embodiments. When the positive electrode 200, the negative electrode 300, and the separator 350 are overwrapped, they are wound in a parabolic shape instead of a cylindrical shape to form a rectangular parallelepiped battery can 100. Inserting.

  Even in such a case, the mesh electrode 400 is disposed on the surface of the negative electrode 300 in the vicinity of the central portion, which is the position farthest from the outer peripheral portion and is considered to be the position where the temperature becomes highest when the cell generates heat. . The ion supply source 401 is also arranged at the same position. The point that the mesh electrode 400, the ion supply source 401, and the negative electrode 300 are connected by the transistor 403 is the same as in the second embodiment.

  With this configuration, only when the potential of the negative electrode material 302 in the vicinity of the cell center detected by the mesh electrode 400 is higher than the negative electrode foil 301 that is the average potential of the negative electrode material 302 of the entire cell, ion supply is performed. A current flows between the source 401 and the negative electrode foil 301, and ions are preferentially supplied from the negative electrode material 302 close to the ion supply source 401.

  Also in this embodiment, the ion supply source 401 uses lithium and is located at the farthest position from the outer periphery of the cell, and at the central axis of the electrode group that seems to be the position where the temperature becomes highest when the cell generates heat. Since it is inserted in the gap, it is possible to selectively lower the potential of the portion where the most potential change is likely to occur.

  The battery cell of this example had a short side of 24 mm and a long side of 70 mm in the cross-sectional view of FIG. 11, the length in the height direction of FIG. 10 was 100 mm, and the electric capacity was about 5.0 Ah. After charging / discharging the cell at a current 82A for 90 seconds with a charge / discharge time of 3000 times, the cell was disassembled, the negative electrode at the center and the outer periphery of the cell was cut out, and the potential difference between the negative electrode at the center and the outer periphery As a result, the potential difference between the cell central portion and the outer peripheral portion was smaller than that of the example and about 0.1 V, and the local potential difference inside the cell could be reduced.

  As described above, in this example, the local potential distribution inside the cell caused by the temperature distribution in the cell due to heat generation during charging and discharging could be eliminated. As a result, it is possible to provide a battery free from capacity deterioration, positive electrode material deterioration, metallic lithium deposition, and the like.

  The present embodiment is the same as the first embodiment except for the following points.

  FIG. 12 is a diagram showing the function of the lithium ion secondary battery cell in this example.

  The present embodiment is characterized in that the mesh electrode 400 is arranged on the surface of the positive electrode 200 near the center, which is the position farthest from the outer periphery of the cell and where the temperature becomes highest when the cell generates heat. It is.

  As in the first embodiment, the mesh electrode 400 and the lithium ion supply source 401 are connected by the diode 402 so that the mesh electrode 400 side is connected to the + polarity side of the diode 402.

In this embodiment, the same LiCoO ₂ as the positive electrode material is used as the ion supply source 401. With respect to this ion supply source 401, the positive electrode material in the present embodiment changes in potential to about 1.2V during charging and to about 0V during discharging in the normal use range.

  The diode 402 has a voltage threshold value so that current flows through the diode 402 only when the central negative electrode becomes high due to lithium ion desorption due to side reaction on the negative electrode surface and accordingly the central positive electrode also becomes high. As shown in FIG. 4, a current having a characteristic that current passes only when there is a potential difference of +1.2 V or more is used.

  In addition, in order to detect that the positive electrode in the central portion is at a high potential, the mesh electrode 400 is attached only to the surface near the central portion of the positive electrode material 202, and an aluminum foil having a hole so that lithium ions can pass therethrough. Is used.

  Here, although the threshold value of the diode 402 is 1.2 V in this embodiment, depending on the purpose of use of the battery cell, only a narrow charge / discharge range is used, and when the potential change of the positive electrode material 202 can be expected to be small, for example, 0 A diode with a small threshold of about .6V may be used. Moreover, you may use metal foils other than aluminum foil also in a mesh electrode material.

  In the battery cell of this example, the diameter was 40 mm and the axial length was 108 mm, but the electric capacity was about 5.0 Ah. In order to obtain an experiment similar to the above-described experiment, the ratio of the current to the electric capacity was adjusted, and charging and discharging with a current 82A and a charging / discharging time of 90 seconds were repeated 3000 times on this cell, and then the cell was disassembled. When the negative electrode at the central part and the outer peripheral part of the cell was cut out and the potential difference between the negative electrode at the central part and the outer peripheral part was measured, the potential difference between the central part and the outer peripheral part of the cell was measured during the negative electrode discharge shown in FIGS. The potential difference was smaller than 0.5 V and about 0.2 V, and the local potential difference inside the cell could be reduced.

  As described above, in this example, the local potential distribution inside the cell caused by the temperature distribution in the cell due to heat generation during charging and discharging could be eliminated. As a result, it is possible to provide a battery free from capacity deterioration, positive electrode material deterioration, metallic lithium deposition, and the like.

  This example is the same as Example 5 except for the following points.

  FIG. 13 is a diagram showing the function of the lithium ion secondary battery cell in this example.

  In the present embodiment, the mesh electrode 400 is disposed on the surface of the positive electrode 200 near the center, which is the position farthest from the outer periphery of the cell and where the temperature is highest when the cell generates heat. Then, although the same as in the fifth embodiment, the mesh electrode 400, the ion supply source 401, and the positive electrode 200 are connected by the transistor 403. Here, the mesh electrode 400 is characterized by being connected to the gate terminal of the transistor 403. The transistor 403 is connected to the positive foil 201 of the positive electrode 200.

  By adopting such a configuration, only when the potential of the positive electrode material 202 in the vicinity of the cell center detected by the mesh electrode 400 is higher than the positive electrode foil 201 which is the average potential of the positive electrode material 202 of the entire cell, ion supply is performed. A current flows between the source 401 and the positive electrode foil 201, and ions are preferentially supplied from the positive electrode material 202 close to the ion supply source 401.

Also in this embodiment, the ion source 401 uses the same LiCoO ₂ as the positive electrode material, and is the farthest position from the outer periphery of the cell, and an electrode group that seems to be the position where the temperature becomes highest when the cell generates heat. Therefore, it is possible to selectively lower the potential of the portion where the change in potential increase is most likely to occur.

  In the battery cell of this example, as in Example 5, the diameter was 40 mm and the axial length was 108 mm, but the electric capacity was about 5.0 Ah. After charging / discharging the cell at a current 82A for 90 seconds with a charge / discharge time of 3000 times, the cell was disassembled, the negative electrode at the center and the outer periphery of the cell was cut out, and the potential difference between the negative electrode at the center and the outer periphery As a result, the potential difference between the cell central portion and the outer peripheral portion was about 0.2 V as in Example 5, and the local potential difference inside the cell could be reduced.

  As described above, in this example, the local potential distribution inside the cell caused by the temperature distribution in the cell due to heat generation during charging and discharging could be eliminated. As a result, it is possible to provide a battery free from capacity deterioration, positive electrode material deterioration, metallic lithium deposition, and the like.

  This example is the same as Example 5 except for the following points.

  FIG. 14 is a diagram showing the function of the lithium ion secondary battery cell in this example.

  In the present embodiment, the mesh electrode 400 is disposed on the surface of the positive electrode 200 near the center, which is the position farthest from the outer periphery of the cell and where the temperature is highest when the cell generates heat. In the same manner as in the fifth embodiment, the mesh electrode 400 and the ion supply source 401 are connected by a resistor 404.

  With such a configuration, as the potential of the positive electrode material 202 in the vicinity of the cell center detected by the mesh electrode 400 becomes larger than that of the ion supply source 401, a larger current is generated between the ion supply source 401 and the mesh electrode 400. The ions are preferentially supplied from the cathode material 202 near the flow and ion supply source 401.

Also in this embodiment, the ion source 401 uses the same LiCoO ₂ as the positive electrode material, and is the farthest position from the outer periphery of the cell, and an electrode group that seems to be the position where the temperature becomes highest when the cell generates heat. Therefore, it is possible to selectively lower the potential of the portion where the change in potential increase is most likely to occur.

  In the battery cell of this example, as in Example 5, the diameter was 40 mm and the axial length was 108 mm, but the electric capacity was about 5.0 Ah. After charging / discharging the cell at a current 82A for 90 seconds with a charge / discharge time of 3000 times, the cell was disassembled, the negative electrode at the center and the outer periphery of the cell was cut out, and the potential difference between the negative electrode at the center and the outer periphery As a result, the potential difference between the cell central portion and the outer peripheral portion was about 0.3 V, and the local potential difference inside the cell could be reduced.

  As described above, in this example, the local potential distribution inside the cell caused by the temperature distribution in the cell due to heat generation during charging and discharging could be eliminated. As a result, it is possible to provide a battery free from capacity deterioration, positive electrode material deterioration, metallic lithium deposition, and the like.

  FIG. 21 is a diagram showing a lithium ion secondary battery module in this example.

  This embodiment is a battery module 500 in which six lithium ion secondary battery cells of Embodiment 1 are connected in series, the state of each battery cell is detected by the cell controller 104, and charge / discharge control is performed. Each battery can 100 is cooled by natural air cooling.

  In this example, since the lithium ion secondary battery cell of Example 1 is used, the local potential distribution inside the cell due to the temperature distribution in the cell due to heat generation during charge / discharge can be eliminated. Therefore, it is possible to eliminate capacity deterioration, positive electrode material deterioration, metallic lithium deposition, etc., and provide a secondary battery module with a long life and high safety.

  The high energy density lithium ion secondary battery of the present invention can be used for portable devices, electric vehicles, power storage and the like.

DESCRIPTION OF SYMBOLS 100 Battery can 101 Electrode group 102 Positive electrode lid 103 Gasket 104 Cell controller 200 Positive electrode 201 Positive electrode foil 202 Positive electrode material 300 Negative electrode 301 Negative electrode foil 302 Negative electrode material 350 Separator 360 Electrolytic solution 400 Mesh electrode 401 Ion supply source 402 Diode 403 Transistor 404 Resistance 500 Battery module

Claims (12)

In a non-aqueous secondary battery that includes a positive electrode, a negative electrode, and an electrolytic solution, and discharges ions from the positive electrode or the negative electrode into the electrolytic solution, or repeatedly charges and discharges,
An ion supply source that elutes ions of the same type as the ions in the electrolytic solution, and a mesh electrode in contact with a part of the surface of the negative electrode,
A non-aqueous secondary battery comprising a diode connected to the ion supply source and the mesh electrode, the mesh electrode being arranged with a positive polarity. In a non-aqueous secondary battery that includes a positive electrode, a negative electrode, and an electrolytic solution, and discharges ions from the positive electrode or the negative electrode into the electrolytic solution, or repeatedly charges and discharges,
An ion source that elutes ions of the same type as the ions in the electrolyte solution, and a mesh electrode that is in contact with a part of the surface of the positive electrode,
A non-aqueous secondary battery comprising a diode connected to the ion supply source and the mesh electrode, the mesh electrode being arranged with a positive polarity. In a non-aqueous secondary battery that includes a positive electrode, a negative electrode, and an electrolytic solution, and discharges ions from the positive electrode or the negative electrode into the electrolytic solution, or repeatedly charges and discharges,
An ion supply source that elutes ions of the same type as the ions in the electrolytic solution, and a mesh electrode in contact with a part of the surface of the negative electrode,
The non-aqueous secondary battery, wherein the ion supply source and the mesh electrode are connected by a resistance element. In a non-aqueous secondary battery that includes a positive electrode, a negative electrode, and an electrolytic solution, and discharges ions from the positive electrode or the negative electrode into the electrolytic solution, or repeatedly charges and discharges,
An ion source that elutes ions of the same type as the ions in the electrolyte solution, and a mesh electrode that is in contact with a part of the surface of the positive electrode,
The non-aqueous secondary battery, wherein the ion supply source and the mesh electrode are connected by a resistance element. In a non-aqueous secondary battery that includes a positive electrode, a negative electrode, and an electrolytic solution, and discharges ions from the positive electrode or the negative electrode into the electrolytic solution, or repeatedly charges and discharges,
An ion supply source that elutes ions of the same type as the ions in the electrolytic solution, and a mesh electrode in contact with a part of the surface of the negative electrode,
A non-aqueous secondary battery comprising a transistor that connects the negative electrode, the ion supply source, and the mesh electrode, and is disposed with the negative electrode as a gate terminal. In a non-aqueous secondary battery that includes a positive electrode, a negative electrode, and an electrolytic solution, and discharges ions from the positive electrode or the negative electrode into the electrolytic solution, or repeatedly charges and discharges,
An ion source that elutes ions of the same type as the ions in the electrolyte solution, and a mesh electrode that is in contact with a part of the surface of the positive electrode,
A non-aqueous secondary battery comprising a transistor that connects the positive electrode, the ion supply source, and the mesh electrode, and is disposed with the positive electrode as a gate terminal. In claims 1 to 6,
The positive electrode is an oxide containing lithium as a positive electrode active material, and is applied to both surfaces of a positive electrode foil that is a current collector,
The negative electrode has a carbon-based material as a negative electrode active material and is applied to both surfaces of a negative electrode foil that is a current collector.
The electrolytic solution is an organic electrolytic solution in which a salt containing lithium is dissolved,
The ion source is a material containing lithium,
The non-aqueous secondary battery, wherein the mesh electrode is in contact with a surface of the positive electrode active material or a surface of the negative electrode active material . In claims 1 to 7,
A sheet-like separator that holds the electrolytic solution is disposed between the positive electrode and the negative electrode,
The positive electrode, the separator, the negative electrode and the separator are alternately overlapped and wound into a cylindrical shape to constitute an electrode group,
The electrode group is inserted into a cylindrical metal can,
The non-aqueous secondary battery, wherein the mesh electrode and the ion supply source are arranged near a central axis of the electrode group. In claims 1 to 7,
A sheet-like separator that holds the electrolytic solution is disposed between the positive electrode and the negative electrode,
The positive electrode, the separator, the negative electrode, and the separator are alternately stacked to form an electrode group by winding in a reverse shape,
The electrode group is inserted into a rectangular parallelepiped metal can,
The non-aqueous secondary battery, wherein the mesh electrode and the ion supply source are arranged near the center of the electrode group. In claims 1 to 7,
A sheet-like separator that holds the electrolytic solution is disposed between the positive electrode and the negative electrode,
The positive electrode, the separator, the negative electrode and the separator are alternately overlapped and wound into a cylindrical shape to constitute an electrode group,
The electrode group is inserted into a cylindrical metal can,
The non-aqueous secondary battery, wherein the mesh electrode and the ion supply source are disposed at a position farthest from an outer peripheral portion of the cylindrical metal can. In claims 1 to 7,
A sheet-like separator that holds the electrolytic solution is disposed between the positive electrode and the negative electrode,
The electrode group is configured by alternately stacking the positive electrode, the separator, the negative electrode, and the separator,
The electrode group is inserted into a rectangular parallelepiped metal can,
The non-aqueous secondary battery, wherein the mesh electrode and the ion supply source are disposed at a position farthest from an outer peripheral portion of the rectangular parallelepiped metal can. In claims 1 to 11,
Using a plurality of non-aqueous secondary batteries, an assembled battery is formed,
A battery module, wherein a positive electrode and a negative electrode of the assembled battery are connected in series or in series-parallel.

Images