JP2013065515A - Secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery which maintains battery performance for a long time.SOLUTION: A secondary battery 1 includes: a lamination electrode body 208 where positive electrode plates 201, negative electrode plates 203, and separators 202 are laminated in the interior thereof sealed by exterior members 206, 207; a secondary battery body 2 for housing an electrolytic solution; an internal pressure sensor 4 for detecting an internal pressure P1 in the secondary battery body 2; a pressurizing device 6 for pressurizing the secondary battery body 2 from the outside; and a pressure adjustment part 20 for adjusting the pressurization conducted by the pressurizing device 6 on the basis of the internal pressure P1 detected by the internal pressure sensor 4. The pressure adjustment part 20 increases the pressurization conducted by the pressurizing device 6 when the internal pressure P1 increases.

Description

  The present invention relates to a secondary battery.

  A safety device for a nickel-metal hydride battery is known in which a pressurized gas is filled in an outer container that houses a nickel-metal hydride battery and the nickel-metal hydride battery is pressurized at a constant pressure (see, for example, Patent Document 1).

JP-A-6-54411

  However, in the above invention, when the internal pressure in the nickel-metal hydride battery rises above the certain pressure, the nickel-metal hydride battery expands, and the electrode plates are easily separated during expansion / contraction due to charge / discharge. There was a risk that the performance (power generation efficiency) would decrease.

  The problem to be solved by the present invention is to provide a secondary battery capable of maintaining the performance of the battery for a long time.

  This invention solves the said subject by increasing the pressurization to a secondary battery main body, when the internal pressure of a secondary battery main body rises.

  According to the present invention, it is possible to maintain the performance of the battery for a long time by suppressing the expansion of the secondary battery body.

FIG. 1 is a schematic diagram of a secondary battery in the first embodiment of the present invention. FIG. 2 is a cross-sectional view of the secondary battery body taken along line II-II in FIG. FIG. 3 is a schematic cross-sectional view for explaining an example of a pressurizing device according to the first embodiment of the present invention (part 1). FIG. 4 is a schematic cross-sectional view for explaining an example of a pressurizing device according to the first embodiment of the present invention (part 2). FIG. 5 is a schematic cross-sectional view of a secondary battery body for explaining the operation of the first embodiment of the present invention. FIG. 6 is a schematic diagram of a secondary battery in the second embodiment of the present invention. FIG. 7 is a schematic cross-sectional view taken along line VII-VII in FIG. FIG. 8 is a schematic diagram showing a modification of the secondary battery in the second embodiment of the present invention. FIG. 9 is a schematic cross-sectional view along the line IX-IX in FIG. FIG. 10 is a diagram illustrating an example of a circuit diagram in which the secondary battery according to the third embodiment of the present invention is incorporated. FIG. 11 is a graph showing the relationship between the SOC and the voltage value of the secondary battery in the third embodiment of the present invention.

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

<< first embodiment >>
FIG. 1 is a schematic diagram of a secondary battery in the present embodiment, FIG. 2 is a cross-sectional view of a secondary battery body along the line II-II in FIG. 1, and FIGS. 3 and 4 are examples of a pressurizing device in the present embodiment. FIG. 5 is a schematic cross-sectional view of a secondary battery main body for explaining the operation of the present embodiment. 3 and 4 correspond to schematic cross-sectional views taken along line III-III in FIG.

  The secondary battery 1 in this embodiment is a battery mounted on a hybrid vehicle, an electric vehicle, or the like. As shown in FIG. 1, the secondary battery 1 includes a secondary battery body 2, a module can 3, an internal pressure sensor 4, an external pressure sensor 5, a pressurizing device 6, and a controller 7. ing.

  As shown in FIG. 2, the secondary battery main body 2 includes three positive electrode plates 201, five separators 202, three negative electrode plates 203, a positive electrode tab 204, and a negative electrode tab 205 (not shown in FIG. 2). (Illustrated), an upper exterior member 206, a lower exterior member 207, and an electrolyte solution (not shown). In the present embodiment, among these, the positive electrode plate 201, the separator 202, and the negative electrode plate 203 are referred to as a laminated electrode body 208, and the laminated electrode body 208 and the electrolytic solution are particularly referred to as a power generation element 209. As such a secondary battery main body 2, a lithium ion secondary battery can be mentioned, for example.

  As shown in the figure, the positive electrode plate 201 of the laminated electrode body 208 is formed on each of the main surfaces of the positive electrode side current collector 201a extending to the positive electrode tab 204 and a part of the positive electrode side current collector 201a. Positive electrode layers 201b and 201c.

  The positive electrode side current collector 201a in the present embodiment is made of an aluminum foil. The positive electrode current collector 201a only needs to be made of an electrochemically stable metal foil. For example, the positive electrode current collector 201a is made of, for example, an aluminum alloy foil, a surface-treated copper foil, or a nickel foil. Or the like.

The positive electrode layers 201b and 201c include a positive electrode active material, a conductive auxiliary agent such as acetylene black, a binder such as polyvinylidene fluoride (PVDF), and a slurry viscosity such as N-methylpyrrolidone (NMP). The positive electrode slurry in which the adjustment solvent is mixed is applied to a part of both main surfaces of the positive electrode side current collector 201a, and is dried and rolled. In this embodiment, lithium manganate (LiMn ₂ O ₄ ) is used as the positive electrode active material, but it is not particularly limited. For example, a lithium composite oxide such as lithium nickelate (LiNiO ₂ ) or lithium cobaltate (LiCoO ₂ ), a chalcogen (S, Se, Te) compound, or the like may be used as the positive electrode active material.

  The negative electrode plate 203 of the laminated electrode body 208 includes a negative electrode side current collector 203a extending to the negative electrode tab 205 (see FIG. 1), and negative electrodes formed on both main surfaces of part of the negative electrode side current collector 203a. Layers 203b and 203c.

  The negative electrode side current collector 203a in the present embodiment is made of a copper foil. The negative electrode side current collector 203a only needs to be made of an electrically stable metal foil, and the negative electrode side current collector 201a is made of, for example, nickel foil, stainless steel foil, or iron foil. Also good.

  The negative electrode layers 203b and 203c include a negative electrode active material that absorbs and releases lithium ions of the positive electrode active material, a conductive auxiliary agent such as acetylene black, a binder such as polyvinylidene fluoride, and a slurry viscosity such as N-methylpyrrolidone. The negative electrode slurry mixed with the adjustment solvent is applied to both main surfaces of a part of the negative electrode side current collector 203a, and is dried and rolled. In this embodiment, graphite is used for the negative electrode active material, but it is not particularly limited. For example, amorphous carbon, non-graphitizable carbon, graphitizable carbon, Si, or the like may be used as the negative electrode active material.

  In particular, when amorphous carbon or non-graphitizable carbon is used as the negative electrode active material, the flatness of the potential during charge / discharge is poor and the output voltage decreases with the amount of discharge. Although unsuitable, when used as a power source for an electric vehicle, it is advantageous because there is no sudden drop in output.

  Here, as shown in FIG. 1, in the secondary battery main body 2 in the present embodiment, the positive electrode tab 204 and the negative electrode tab 205 are led out side by side from one side of the exterior members 206 and 207. For this reason, in FIG. 2, the cross section from the positive electrode plate 201 to the positive electrode tab 204 of the laminated electrode body 208 is illustrated, and the cross section from the negative electrode plate 203 to the negative electrode tab 205 is omitted, but the negative electrode plate 203 and the negative electrode The tab 205 also has substantially the same structure as the positive electrode plate 201 and the positive electrode tab 204 shown in FIG. However, the positive electrode plate 201 (positive current collector 201a) between the end of the laminated electrode body 208 and the positive electrode tab 204, and the negative electrode plate 203 (with the negative electrode tab 205 between the end of the laminated electrode body 208 and the negative electrode tab 205 ( The negative electrode side current collector 203a) is not particularly shown, but is cut out by half or less so as not to contact each other in plan view.

  The separator 202 of the laminated electrode body 208 prevents a short circuit between the positive electrode plate 201 and the negative electrode plate 203 and may have a function of holding an electrolytic solution. Separator 202 in the present embodiment is made of a microporous film made of polyolefin such as polyethylene (PE). Such a separator 202 also has a function of interrupting the current by closing holes of the layer due to heat generation when an overcurrent flows.

  The separator 202 in the present embodiment is not limited to a single-layer film such as polyolefin, but is composed of a three-layer structure in which a polypropylene film is sandwiched with a polyethylene film, or a laminate of a polyolefin microporous film and an organic nonwoven fabric or the like. May be. Thus, by forming the separator 202 in multiple layers, various functions such as an overcurrent prevention function, an electrolyte solution holding function, and a shape maintaining (stiffness improvement) function of the separator 202 can be provided.

  In the laminated electrode body 208 described above, the positive electrode plates 201 and the negative electrode plates 203 are alternately laminated via the separators 202. The three positive plates 201 are respectively connected to the positive tab 204 made of metal foil via the positive current collector 201a, and the three negative plates 203 are connected to the negative current collector 203a. Similarly, they are connected to the negative electrode tab 205 made of metal foil.

  In addition, the positive electrode plate 201, the separator 202, and the negative electrode plate 203 of the laminated electrode body 208 are not limited to the above number. For example, a laminated electrode body can be constituted by one positive electrode plate, two separators, and one negative electrode plate, and the number of positive electrode plates, separators and negative electrode plates can be selected as necessary. Can do.

  The material constituting the positive electrode tab 204 and the negative electrode tab 205 is not particularly limited as long as it is an electrochemically stable metal material. For example, the positive electrode tab 204 can be made of an aluminum foil, an aluminum alloy foil, a copper foil, a nickel foil, or the like, like the positive electrode side current collector 201a. Further, the negative electrode tab 205 can be formed of a copper foil, a nickel foil, a stainless steel foil, an iron foil, or the like, similarly to the negative electrode side current collector 203a described above. In the present embodiment, the metal foil itself constituting the current collectors 201a and 203a of the electrode plates 201 and 203 is extended to the electrode tabs 204 and 205, whereby the electrode plates 201 and 203 are directly attached to the electrode tabs 204 and 205. Although connected, the current collectors 201a and 203a of the electrode plates 201 and 203 and the electrode tabs 204 and 205 are connected by a material or component different from the metal foil constituting the current collectors 201a and 203a. Also good.

  Here, in the present embodiment, both the positive electrode tab 204 and the negative electrode tab 205 are arranged so as to be led out from the same side of the secondary battery body 2 (the exterior members 206 and 207). The arrangement of the negative electrode tab 205 is not particularly limited. For example, you may arrange | position so that the positive electrode tab 204 and the negative electrode tab 205 may be derived | led-out from the mutually opposing edge | side.

  The above-described laminated electrode body 208 is accommodated and sealed between an upper exterior member 206 molded in a cup shape as shown in FIG. 2 and a flat lower exterior member 207. The upper exterior member 206 and the lower exterior member 207 in this embodiment are both made of a laminate material (laminate film) made of an inner resin layer, a metal layer, and an outer resin layer, although not particularly illustrated.

  The inner resin layer of the laminate material can be composed of, for example, a resin film excellent in electrolytic solution resistance and heat fusion properties such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, or ionomer. Moreover, about a metal layer, it can be comprised with metal foil, such as aluminum, for example, and about an outer side resin layer, it is comprised with the resin film excellent in electrical insulation, such as a polyamide-type resin and a polyester-type resin, for example. Can do.

These exterior members 206 and 207 enclose part of the electrode tabs 204 and 205 and the laminated electrode body 208, and inject an electrolyte such as LiPF ₆ / EC + DEC into the space formed by the exterior members 206 and 207. After the space is in a vacuum state, the outer peripheral portions of the exterior members 206 and 207 are heat-sealed by hot pressing. Accordingly, a part of the electrode tabs 204 and 205 and the power generation element 209 are accommodated and sealed between the exterior members 206 and 207. The above-mentioned “LiPF ₆ / EC + DEC” is obtained by dissolving lithium hexafluorophosphate (LiPF 6) in a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC). In the following, “inside of the secondary battery main body 2” means the inside of the space sealed by the exterior members 206 and 207 and filled with the electrolytic solution.

The electrolytic solution is not limited to LiPF ₆ / EC + DEC, and may be, for example, a solution obtained by dissolving a lithium salt such as lithium perchlorate or lithium borofluoride in an organic liquid solvent. Examples of the organic liquid solvent include ester solvents such as propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), and methyl ethyl carbonate. The organic liquid solvent is not limited to this, and an organic liquid solvent prepared by mixing and preparing an ester solvent such as γ-butylactone (γ-BL) or an ether solvent such as diethyloxyethane (DEE) may be used. it can.

  As shown in FIG. 1, the module can 3 is a box-shaped member that houses a battery module including a plurality of secondary battery bodies 2 in an internal space 31. In FIG. 1, only one secondary battery main body 2 is shown, and the other secondary battery main bodies are not shown. Moreover, in this embodiment, although the battery module is comprised by the four secondary battery main bodies 2 (refer FIG. 3), the number of the secondary battery main bodies 2 which comprise a battery module is not specifically limited.

  The space 31 of the module can 3 is sealed except that it is connected to the pressurizing device 6 and the wiring of the pressure sensors 4 and 5 is led out. Such a module can 3 is made of, for example, stainless steel, but the material of the module can 3 is not particularly limited.

  The internal pressure sensor 4 is a device that is housed inside the secondary battery body 2 and detects the internal pressure P1 inside the secondary battery body 2. The internal pressure sensor 4 is connected to the controller 7 by wiring, and outputs a signal of the detected internal pressure P1 to the controller 7.

  The external pressure sensor 5 is a device that is housed in the module can 3 together with the secondary battery body 2 and detects the external pressure P2 applied to the secondary battery body 2 by the pressurizing device 6. The external pressure sensor 5 is not housed inside the secondary battery body 2 and is disposed outside the secondary battery body 2 and inside the module can 3. The external pressure sensor 5 is also connected to the controller 7 by wiring, and outputs a signal of the detected external pressure P2 to the controller 7.

  The pressurizing device 6 is a device that pressurizes the secondary battery body 2 based on a command from the controller 7. As such a pressurizing device 6, a compressor 61 that feeds pressurized fluid into the space 31 of the module can 3 can be exemplified as shown in FIG. 3. In this case, the flow path 6a is provided between the module can 3 and the compressor 61, and both are connected. Examples of such fluid include air, but are not particularly limited thereto.

  In this way, by increasing the pressure in the space 31 of the module can 3 using the compressor 61, the secondary battery main body 2 can be uniformly pressurized as a whole. Thereby, in the secondary battery main body 2, since it is suppressed that the space | interval of the positive electrode plate 201, the separator 202, and the negative electrode plate 203 becomes non-uniform | heterogenous, while being able to suppress decline in power generation efficiency, local stress It is possible to suppress non-uniform degradation of the secondary battery body 1 (laminated electrode body 208) due to the application of.

  Further, as shown in FIG. 4, the pressing device 62 is configured to press the secondary battery body 2 from above and below via the module can 3, and although not particularly shown, the secondary battery body You may comprise with the press apparatus which presses 2 directly. When the secondary battery body 2 is directly pressed, the laminated electrode body 208 is pressed through the exterior members 206 and 207, or the portion where the exterior members 206 and 207 are bonded is pressed. May be. An actuator such as a motor can be used for such a pressing device.

  The controller 7 is a device that acquires a signal of the pressure detected by the pressure sensors 4 and 5 and controls the pressurizing device 6 based on the detected pressure. Such a controller 7 can be constituted by, for example, a CPU (Central Processing Unit).

  The controller 7 calculates a differential pressure P3 (P3 = P2-P1) between the external pressure P2 detected by the external pressure sensor 5 and the internal pressure P1 detected by the internal pressure sensor 4, and the differential pressure P3 is a predetermined value. When the pressure is lower than P4 (positive value), the pressure applied to the secondary battery body 2 by the pressurizing device 6 is increased so that the differential pressure P3 becomes equal to or greater than the predetermined value P4 (P3 ≧ P4). Furthermore, the controller 7 maintains the pressurization by the pressurizing device 6 so as to maintain the state where the differential pressure P3 is higher than the predetermined value P4.

  For example, as shown in FIG. 5, when gas G is generated inside the secondary battery main body 2 due to charge / discharge or deterioration, and the internal pressure P1 of the secondary battery main body 2 increases, the controller 7 increases the pressure. A command is output to the pressurizing device 6 so as to increase the pressurization by the device 6.

  In the present embodiment, when at least one of the four secondary battery bodies 2 constituting the battery module has the differential pressure P3 lower than the predetermined value P4, the controller 7 A command to increase the pressure applied to the secondary battery body 2 is output, and the secondary battery body 2 is pressurized with a higher pressure.

  For example, when the predetermined value P4 of the differential pressure is 1000 hPa, when the differential pressures P3 in the four secondary battery main bodies 2 become 1000 hPa, 1000 hPa, 1000 hPa, and 990 hPa, the controller 7 sets the differential pressure P3 of 990 hPa to 1000 hPa. The pressure applied by the pressure device 6 is increased by 10 hPa.

  At this time, the pressurizing device 6 simultaneously pressurizes other secondary battery main bodies 2 whose original differential pressure P3 is 1000 hPa, so the differential pressure P3 of the secondary battery main body 2 (original 1000 hPa) ) Is 1010 hPa. Thus, the effect that the expansion | swelling of the secondary battery main body 2 is suppressed is maintained for the part which the differential pressure P3 becomes large. That is, in the present embodiment, the secondary battery body 2 may be pressurized so that the differential pressure P3 is higher than the predetermined value P4. For example, in the above example, the secondary battery body 2 may be pressurized by the pressurizing device 6 so that the differential pressure P3 is 1020 hPa or 1040 hPa.

  Here, in the present embodiment, the external pressure sensor 5 and the controller 7 constitute a pressure adjusting unit 20 that adjusts the external pressure by the pressurizing device 6.

  Next, the operation in this embodiment will be described.

  When gas is generated inside the secondary battery body due to charging / discharging or deterioration and the secondary battery body expands, the positive electrode plate, negative electrode plate, and separator inside the secondary battery body easily separate from each other due to changes accompanying charging / discharging. Therefore, the performance (power generation efficiency) of the secondary battery body may be reduced.

  On the other hand, in this embodiment, when the internal pressure of the secondary battery main body is detected and the internal pressure increases, the secondary battery main body is pressurized from the outside by the pressurizing device. Can be suppressed. Thereby, since it is suppressed that a positive electrode plate, a negative electrode plate, and a separator mutually separate, the performance of a battery can be maintained long.

  Further, in the present embodiment, pressurization by the pressurizer is performed so that the differential pressure between the external pressure applied to the secondary battery main body by the pressurizer and the internal pressure of the secondary battery main body becomes a predetermined value or more. It is adjusted. That is, in this embodiment, since the secondary battery body is pressurized so that the external pressure is always greater than the internal pressure, the expansion of the secondary battery body is reliably suppressed. For this reason, in this embodiment, it is possible to maintain the performance of the battery longer.

  Next, a second embodiment will be described.

<< Second Embodiment >>
6 is a schematic diagram of the secondary battery in the present embodiment, FIG. 7 is a schematic cross-sectional view taken along line VII-VII in FIG. 6, and FIG. 8 is a schematic diagram showing a modification of the secondary battery in the present embodiment. 9 is a schematic sectional view taken along line IX-IX in FIG.

  As shown in FIGS. 6 and 7, the secondary battery 1 a in the present embodiment is different from the first embodiment in that a gas reservoir member 8 is provided inside the secondary battery main body 2, but other than that. Is the same as in the first embodiment. Only the parts different from the first embodiment will be described below, and the same parts as those of the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

  As shown in FIG. 7, the gas reservoir member 8 is composed of a stent 8a having a hollow 8b formed therein. The stent 8a is formed so that the gas generated inside the secondary battery body 2 can be vented while the electrolyte solution of the secondary battery body 2 can be prevented from penetrating. Such a stent 8a can be made of, for example, polypropylene.

  As shown in FIGS. 6 and 7, the gas reservoir member 8 is disposed between the laminated electrode body 208 and the sealing portion 210 of the exterior members 206 and 207 inside the secondary battery body 2. . The sealing portion 210 is a portion bonded to each other at the outer edge portions of the exterior members 206 and 207, and is a portion that seals the laminated electrode body 208 and the electrolyte inside the secondary battery body 2. is there. In the present embodiment, the outer edge portion (the left side in FIG. 6) of the exterior members 206 and 207 to be sealed last in the sealing portion 210 is referred to as a “final sealing portion 210a”. .

  In the present embodiment, the gas reservoir member 8 is disposed only between the final sealing portion 210a and the laminated electrode body 208, but there is no particular limitation. For example, as shown in FIGS. 8 and 9, in addition to disposing the gas reservoir member 8 between the final sealing portion 210a and the laminated electrode body 208, the sealing portions 210 other than the final sealing portion 201a. The gas reservoir member 8 may be disposed between the laminated electrode body 208 and the laminated electrode body 208.

  In the present embodiment, even if gas is generated inside the secondary battery main body due to charging / discharging or deterioration of the secondary battery main body, the gas is absorbed into the space inside the gas reservoir member. Thereby, since the raise of the internal pressure of a secondary battery main body can be suppressed and expansion | swelling of a secondary battery main body can be suppressed, the performance of a battery can be maintained long.

  In this embodiment, since the gas reservoir member is disposed between the sealing portion and the laminated electrode body, it is possible to prevent gas from entering between the upper and lower main surfaces of the laminated electrode body and the exterior member. ing. For this reason, the pressurization by the pressurizing device can be efficiently applied to the laminated electrode body, and the decrease in power generation efficiency due to the separation of the electrode plates can be suppressed.

  Further, in this embodiment, since the gas reservoir member is disposed between the final sealing portion and the laminated electrode body, after injecting the electrolyte into the space between the exterior members, the interior of the secondary battery body The gas reservoir member can be easily arranged. For this reason, the deterioration of the productivity of a secondary battery accompanying providing the gas reservoir member in the secondary battery main body can be suppressed.

  Also in the present embodiment, as in the first embodiment, the internal pressure inside the secondary battery body is detected, and when the internal pressure increases, the pressurization device pressurizes the secondary battery body. Therefore, the expansion of the secondary battery body can be suppressed, and the performance of the battery can be maintained for a long time.

  Also in the present embodiment, as in the first embodiment, the differential pressure between the external pressure applied to the secondary battery body by the pressurizer and the internal pressure of the secondary battery body is equal to or greater than a predetermined value. Since the pressurization by the pressurizing device is adjusted, the expansion of the secondary battery body can be reliably suppressed. For this reason, the performance of the battery can be maintained longer.

  Next, a third embodiment will be described.

<< Third Embodiment >>
FIG. 10 is a diagram illustrating an example of a circuit diagram in which the secondary battery according to the present embodiment is incorporated, and FIG. 11 is a graph illustrating the relationship between the SOC and the voltage value of the secondary battery according to the present embodiment.

  The secondary battery 1b in the present embodiment is connected to a motor via an inverter in a hybrid vehicle or an electric vehicle, for example, as shown in a circuit diagram shown in FIG. In such an electric circuit, the inverter converts the DC power of the secondary battery 1b into AC power and drives the motor. Further, in such an electric circuit, when the automobile is braked, the regenerative energy is absorbed and the secondary battery is charged. In the figure, only two secondary battery main bodies 2 are shown, but the number of secondary battery main bodies 2 is not particularly limited.

  The secondary battery 1b in the present embodiment is different from the first embodiment in that it includes a temperature sensor 91, a voltmeter 92, and a memory 93, but otherwise the first embodiment. It is the same. Only the parts different from the first embodiment will be described below, and the same parts as those of the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

  The temperature sensor 91 is disposed inside the secondary battery body 1 and detects the temperature inside the secondary battery body 2. The temperature sensor 91 outputs a detected temperature signal to the controller 7. The voltmeter 92 is connected in parallel to the secondary battery body 2 and detects the voltage of the secondary battery body 2. The voltmeter 92 also outputs a detected voltage signal to the controller 7.

  The memory 93 stores the relationship between the SOC (State Of Charge) and the voltage shown in FIG. 11, and the secondary when the secondary battery body 2 is a predetermined SOC (for example, SOC 30%, 50%, and 90%). The pressure threshold value P5 of the internal pressure of the battery body 2 and the pressure threshold value P6 of the external pressure are stored. Furthermore, the memory 93 stores a pressure threshold value P7 for internal pressure and a pressure threshold value P8 for external pressure when the internal temperature of the secondary battery body 2 is a predetermined temperature (for example, 10 ° C., 15 ° C., 20 ° C. and 25 ° C.). doing. The memory 93 can communicate with the controller 7.

  The controller 7 in this embodiment is based on the pressure threshold value P5 of the internal pressure at the predetermined SOC stored in the memory 93 and the internal pressure P1 detected by the internal pressure sensor 4, and the deterioration of the secondary battery body 2 is detected. Determine the presence or absence. This point will be described in detail below.

  First, the controller 7 accesses the memory 93 and calculates the SOC of the secondary battery body 2 based on the voltage detected by the voltmeter 92 from the relationship between the SOC and the voltage shown in FIG.

  When the calculated SOC is a predetermined SOC, the controller 7 determines the internal pressure P1 detected by the internal pressure sensor 4 and the pressure threshold P5 of the internal pressure at the predetermined SOC stored in the memory 93. Compare When the internal pressure P1 is higher than the pressure threshold value P5 (P1> P5), the controller 7 determines that the secondary battery main body 2 has deteriorated because gas is generated inside the secondary battery main body 2. to decide. On the other hand, when the internal pressure P1 is lower than the pressure threshold value P5 (P1 ≦ P5), the controller 7 determines that the secondary battery body 2 has not deteriorated due to gas generation.

  In addition, the controller 7 according to the present embodiment is provided with the secondary battery main body 2 based on the pressure threshold value P6 of the external pressure at the predetermined SOC stored in the memory 93 and the external pressure P2 detected by the external pressure sensor 5. Also check for deterioration. This point will be described in detail below.

  First, the controller 7 calculates the SOC based on the voltage of the secondary battery body 2 detected by the voltmeter 92 as described above.

  Next, when the calculated SOC is the predetermined SOC, the controller 7 detects the external pressure pressure threshold value P6 at the predetermined SOC stored in the memory 93 and the external pressure detected by the external pressure sensor 5. Compare with P2. When the external pressure P2 is higher than the pressure threshold value P6 (P2> P6), the controller 7 changes the external pressure in accordance with the internal pressure, so that gas is generated inside the secondary battery body 2. Therefore, it is determined that the secondary battery main body 2 has deteriorated. On the other hand, the controller 7 determines that the secondary battery body 2 has not deteriorated when the external pressure P2 is lower than the pressure threshold P6 (P2 ≦ P6).

  Further, the controller 7 in the present embodiment is a secondary battery based on the pressure threshold P7 of the internal pressure when the temperature inside the secondary battery body 2 is a predetermined temperature and the internal pressure P1 detected by the internal pressure sensor 4. The presence / absence of deterioration of the main body 2 is also determined. This point will be described in detail below.

  First, the controller 7 acquires a signal of the temperature detected by the temperature sensor 91. Next, when the temperature detected by the temperature sensor 91 is a predetermined temperature, the pressure threshold P7 of the internal pressure at the predetermined temperature stored in the memory 93 and the internal pressure detected by the internal pressure sensor 4 are stored. Compare with P1. When the internal pressure P1 is higher than the pressure threshold value P7 (P1> P7), the controller 7 determines that the secondary battery body 2 has deteriorated because gas is generated inside the secondary battery body 2. to decide. On the other hand, the controller 7 determines that the secondary battery body 2 has not deteriorated when the internal pressure P1 is lower than the pressure threshold P7 (P1 ≦ P7).

  Further, the controller 7 in the present embodiment is based on the pressure threshold P8 of the external pressure when the temperature inside the secondary battery main body 2 described above is a predetermined temperature and the external pressure P2 detected by the external pressure sensor 5. The presence or absence of deterioration of the secondary battery body 2 is also determined. This point will be described in detail below.

  First, the controller 7 acquires a signal of the temperature detected by the temperature sensor 91. Next, when the temperature detected by the temperature sensor 91 is a predetermined temperature, the controller 7 detects the pressure threshold P8 of the external pressure at the predetermined temperature stored in the memory 93 and the external pressure sensor 5 detects. The external pressure P2 is compared. When the external pressure P2 is higher than the pressure threshold value P8 (P2> P8), the controller 7 changes the external pressure according to the internal pressure, so that gas is generated inside the secondary battery body 2. Therefore, it is determined that the secondary battery main body 2 has deteriorated. On the other hand, the controller 7 determines that the secondary battery body 2 has not deteriorated when the external pressure P2 is lower than the pressure threshold value P8 (P2 ≦ P8).

  When the controller 7 determines that the secondary battery main body 2 has deteriorated, the controller 7 outputs a signal for generating an alarm such as an alarm. For example, when the secondary battery 1b in the present embodiment is mounted on an automobile, the controller 7 outputs a signal for generating an alarm sound on a speaker mounted on the automobile. Alternatively, the controller 7 outputs a signal that causes the monitor to display character information and a graphic indicating that the battery has deteriorated, for a navigation system mounted on the automobile.

  As described above, in the present embodiment, by using the internal pressure sensor 4 and the external pressure sensor 5 for calculating the differential pressure, the pressure threshold of the internal pressure at the predetermined SOC and the predetermined temperature, and the internal pressure sensor are used. Comparing the detected internal pressure to determine the deterioration of the secondary battery body, or comparing the pressure threshold of the external pressure at a predetermined SOC or a predetermined temperature with the external pressure detected by the external pressure sensor The deterioration of the secondary battery body is judged. That is, in the present embodiment, it is not simply determined whether or not the secondary battery main body is deteriorated based on the increase or decrease in pressure, but the state of the secondary battery main body and the pressure detected by each pressure sensor Based on the above, the presence or absence of deterioration of the secondary battery body is determined. Thereby, in this embodiment, the said judgment can be performed correctly.

  Further, in the present embodiment, by determining whether or not the secondary battery main body has deteriorated, for example, the state of deterioration of the secondary battery main body can be announced to a driver of an automobile on which the secondary battery is mounted. Thereby, it is possible to inform the driver of the replacement time of the secondary battery. In addition, it is possible to respond from the support center side by transmitting a signal of deterioration state to the support center that manages the state of the automobile.

  In the present embodiment, the presence or absence of deterioration of the secondary battery main body is executed as described above based on the state of the secondary battery main body and the internal pressure or the external pressure. You may comprise so that the generation amount of the gas which generate | occur | produced inside the secondary battery main body may be calculated. Specifically, the internal pressure at a predetermined temperature with a predetermined SOC obtained in advance in an experiment is stored in a memory, and gas is generated from the product of the difference between the internal pressure detected by the internal pressure sensor and the space volume in the battery. The amount may be calculated.

  Also in the present embodiment, as in the first embodiment, the internal pressure inside the secondary battery body is detected, and when the internal pressure increases, the pressurization device pressurizes the secondary battery body. Therefore, the expansion of the secondary battery body can be suppressed, and the performance of the battery can be maintained for a long time.

  Also in the present embodiment, as in the first embodiment, the differential pressure between the external pressure applied to the secondary battery body by the pressurizer and the internal pressure of the secondary battery body is equal to or greater than a predetermined value. Since the pressurization by the pressurizing device is adjusted, the expansion of the secondary battery body can be reliably suppressed. For this reason, the performance of the battery can be maintained longer.

  In the present embodiment, a gas reservoir may be provided in the secondary battery main body as in the second embodiment. Thereby, similarly to 2nd Embodiment, the performance of a battery can be maintained longer.

  The internal pressure sensor 4 in the first to third embodiments described above corresponds to an example of the internal pressure detecting means of the present invention, and the pressurizing device 6 in the first to third embodiments is the pressurizing of the present invention. The pressure adjustment unit 20 in the first to third embodiments corresponds to an example of the pressure adjustment means of the present invention, and the external pressure sensor 5 in the first to third embodiments corresponds to the external pressure of the present invention. The controller 7 in the first to third embodiments corresponds to an example of the detection means, the pressure control means of the present invention corresponds to an example, and the gas reservoir member 8 in the second embodiment corresponds to an example of the gas reservoir portion of the present invention. The stent 8a in the second embodiment corresponds to an example of the ventilation member of the present invention, the voltmeter 92 and the controller 7 in the third embodiment correspond to an example of the SOC calculation means of the present invention, and the third embodiment. Contro in 7 corresponds to an example of the battery state diagnosis means of the present invention, the memory 93 in the third embodiment corresponds to an example of the storage means of the present invention, and the temperature sensor 91 in the third embodiment corresponds to the temperature detection means of the present invention. It corresponds to an example.

  The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Secondary battery 2 ... Secondary battery main body 3 ... Module can 4 ... Internal pressure sensor 5 ... External pressure sensor 6 ... Pressurizing device 7 ... Controller 8 ... Gas reservoir member

Claims (9)

A secondary battery body containing a laminated electrode body in which a positive electrode plate, a negative electrode plate, and a separator are laminated, and an electrolyte solution, sealed inside by an exterior member;
An internal pressure detecting means for detecting an internal pressure inside the secondary battery body;
Pressurizing means for pressurizing the secondary battery body from the outside;
Pressure adjusting means for adjusting the pressurization by the pressurizing means based on the internal pressure detected by the internal pressure detecting means,
The secondary battery according to claim 1, wherein the pressure adjusting unit increases the pressurization by the pressurizing unit when the internal pressure increases. The secondary battery according to claim 1,
The pressure adjusting means includes an external pressure detecting means for detecting an external pressure applied to the secondary battery body by the pressurizing means, and a differential pressure between the external pressure and the internal pressure becomes a predetermined value or more. Thus, the secondary battery is characterized by adjusting the pressurization by the pressurizing means. The secondary battery according to claim 2,
The pressure adjusting means further includes a pressure control means for calculating the differential pressure between the external pressure and the internal pressure and controlling the pressurizing means so that the differential pressure becomes equal to or greater than the predetermined value. A secondary battery characterized by comprising: The secondary battery according to any one of claims 1 to 3,
A gas reservoir for collecting gas generated inside the secondary battery body;
The gas reservoir has a ventilation member having air permeability to the gas and impermeable to the electrolyte,
A hollow capable of receiving the gas is formed inside the ventilation member,
2. The secondary battery according to claim 1, wherein the gas reservoir is disposed between the sealing part on which the exterior member is bonded and the laminated electrode body inside the secondary battery main body. The secondary battery according to claim 4,
The secondary battery according to claim 1, wherein the gas reservoir is disposed between the laminated electrode body and a final sealing portion that is bonded to the exterior member lastly in the secondary battery main body. The secondary battery according to any one of claims 1 to 5,
SOC calculating means for calculating the SOC of the secondary battery body;
Storage means for storing a pressure threshold value of the internal pressure at a predetermined SOC;
Battery state diagnosis means for determining the presence or absence of deterioration of the secondary battery body,
The battery state diagnosing means determines that the secondary battery main body has deteriorated when the internal pressure detected by the internal pressure detecting means is higher than the pressure threshold value in the state of the predetermined SOC. Secondary battery. The secondary battery according to claim 1,
The pressure adjusting means has an external pressure detecting means for detecting an external pressure applied to the secondary battery body by the pressurizing means,
The secondary battery is
SOC calculating means for calculating the SOC of the secondary battery body;
Storage means for storing a pressure threshold value of the external pressure at a predetermined SOC;
Battery state diagnosis means for determining the presence or absence of deterioration of the secondary battery body,
The battery state diagnosis unit determines that the secondary battery body has deteriorated when the external pressure detected by the external pressure detection unit is higher than the pressure threshold in the state of the predetermined SOC. Secondary battery. The secondary battery according to any one of claims 1 to 5,
Temperature detecting means for detecting the temperature inside the secondary battery body;
Storage means for storing a pressure threshold value of the internal pressure at a predetermined temperature;
Battery state diagnosis means for determining the presence or absence of deterioration of the secondary battery body,
The battery state diagnosis unit is configured such that when the internal pressure detected by the internal pressure detection unit is higher than the pressure threshold in the state where the inside of the secondary battery body is at the predetermined temperature, the secondary battery body is A secondary battery characterized in that it is judged to be deteriorated. The secondary battery according to claim 1,
The pressure adjusting means has an external pressure detecting means for detecting an external pressure applied to the secondary battery body by the pressurizing means,
The secondary battery is
Temperature detecting means for detecting the temperature inside the secondary battery body;
Storage means for storing a pressure threshold value of the external pressure at a predetermined temperature;
Battery state diagnosis means for determining the presence or absence of deterioration of the secondary battery body,
The battery state diagnosing means, when the internal pressure of the secondary battery main body is at the predetermined temperature and the external pressure detected by the external pressure detecting means is higher than the pressure threshold, A secondary battery characterized in that the main body is judged to be deteriorated.

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