JP2015122169A - Method of inspecting all-solid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of improving the precision of determinations on whether there is a fine short circuit and whether there is a latent defect which may cause the fine short circuit for a method of inspecting an all-solid battery.SOLUTION: There is provided a method of inspecting an all-solid battery, the method including the steps of: (i) finding a voltage drop amount ΔV1 due to a self-discharge of the battery after charging the battery; (ii) determining whether the voltage drop amount ΔV1 exceeds a predetermined first reference value; (iii) charging the battery under pressure exceeding the restraint pressure in use of the battery, and then finding a voltage drop amount ΔV2 due to a self-discharge by letting the battery discharge itself when the voltage drop amount ΔV1 exceeds the predetermined first reference value; (iv) determining whether the voltage drop amount ΔV2 exceeds a predetermined second reference value; and (v) determining the battery as a defective when the voltage drop amount ΔV2 exceeds the predetermined second reference value.

Description

  The present invention relates to an inspection method for an all-solid-state battery, and more particularly to an inspection method for an all-solid-state battery with improved accuracy in determining whether or not there is a fine short circuit.

  Conventionally, secondary batteries such as lithium ion secondary batteries and nickel / hydrogen storage batteries have a positive electrode layer and a negative electrode layer laminated via a separator, and a wound electrode group is housed in a container and impregnated with an electrolyte. After that, it is manufactured by obtaining processes such as initial charging and aging. As an inspection method for determining a defective secondary battery (defective product) that may cause a fine short circuit in the manufacturing process of the secondary battery, Patent Document 1 discloses a lithium secondary battery at a predetermined environmental temperature. An inspection method characterized by determining a voltage drop after being left for a predetermined time under and determining that a conductive foreign matter is present in the lithium secondary battery when the obtained voltage drop is greater than a preset voltage drop reference Proposed. In Patent Document 2, a current flowing along with the application of an inspection voltage is measured while applying an inspection voltage between a pair of electrode plates, and a defect that leads to an internal short circuit of the electrode group is compared with a preset current. Patent Document 3, which proposes a method characterized by the following, is a short circuit inspection of a battery formed by inserting an electrode plate group formed by laminating a positive electrode plate and a negative electrode plate through a separator into a battery case. In the method, it is proposed to inspect the short-circuit failure while pressurizing the electrode plate group before inserting the electrode plate group into the battery case. Patent Document 4 proposes a method of discharging to a second SOC lower than the first SOC and detecting a short-circuit of the secondary battery under an environmental temperature lower than a predetermined temperature.

Japanese Patent Laid-Open No. 2005-158643 JP 2010-32346 A JP 2001-236985 A JP 2011-69775 A

  The above prior art is a method for detecting a micro short circuit caused by conductive foreign matters such as metallic foreign matters being dissolved in the electrolytic solution and deposited on the negative electrode in an electrolyte secondary battery in which the electrolyte is an electrolytic solution. is there. On the other hand, in an all solid state battery having a solid electrolyte layer between a positive electrode and a negative electrode, when a conductive foreign matter such as a metallic foreign matter is present in the solid electrolyte layer, the metallic foreign matter is not dissolved in the solid electrolyte. As in the secondary battery, the phenomenon that the metal foreign matter is dissolved in the electrolyte and deposited on the negative electrode does not occur. Therefore, the conventional short-circuit detection method for the electrolyte-based secondary battery cannot be applied to the all-solid battery. Further, in an all-solid battery, since the electrolyte is solid, if a foreign substance such as a metallic foreign substance is present in the solid electrolyte layer, stress is generated around the foreign substance. For example, the battery protrudes outward at a part where the foreign substance exists. Swell in a shape. When a load is applied to such a part due to vibration or battery displacement during use of the battery, there is a defect such as a crack that causes a micro short circuit in the solid electrolyte layer that plays a role in insulating between the positive electrode and the negative electrode. May occur. Therefore, before the manufactured all-solid-state battery is distributed to the market (before shipping), an inspection method for determining whether or not there is a fine short-circuit or a potential defect that may cause a fine short-circuit with high accuracy. Is required.

  Therefore, an object of the present invention is to provide an inspection method for an all-solid-state battery that can determine with high accuracy the presence or absence of a micro short circuit and the presence or absence of a potential defect that causes a micro short circuit.

In one embodiment, the present invention is an inspection method for an all-solid battery,
An inspection method for an all-solid battery,
(I) a step of obtaining a voltage drop ΔV1 due to self-discharge of the battery after charging the battery;
(Ii) a step of determining whether or not the voltage drop amount ΔV1 exceeds a predetermined first reference value;
(Iii) When the voltage drop amount ΔV1 exceeds a predetermined first reference value, the battery is charged under a pressure exceeding the binding pressure when the battery is used, and self-discharged to obtain a voltage drop amount ΔV2 due to self-discharge. The desired process,
(Iv) determining whether or not the voltage drop amount ΔV2 exceeds a predetermined second reference value; and (v) if the voltage drop amount ΔV2 exceeds a predetermined second reference value, A process for determining that the product is non-defective,
An inspection method for an all solid state battery is provided.

In the second embodiment, the present invention is an inspection method for an all-solid-state battery,
(I) a step of obtaining a voltage drop ΔV1 due to self-discharge of the battery after charging the battery;
(Ii) a step of determining whether or not the voltage drop amount ΔV1 exceeds a predetermined first reference value;
(Iii) When the voltage drop amount ΔV1 exceeds a predetermined first reference value, the charge / discharge capacity measurement is performed on the battery at a constant current and constant voltage, and the coulomb efficiency, the constant current capacity decrease amount and the constant voltage capacity decrease are measured. The process of determining the quantity,
(Iv) (a) Whether the coulomb efficiency obtained in step (iii) is less than a predetermined reference value, or (b) the constant current capacity decrease amount obtained in step (iii) is a predetermined first (C) determining whether or not the constant voltage capacity reduction amount obtained in step (iii) exceeds a predetermined second capacity reference value; and (v) ) When the coulomb efficiency is less than a predetermined reference value, or when the constant current capacity decrease amount exceeds a predetermined first capacity reference value, or the constant voltage capacity decrease amount is equal to a predetermined second capacity reference value. A process of determining a battery as defective when exceeding
An inspection method for an all solid state battery is provided.

FIG. 1 is a flowchart of an embodiment of the all-solid-state battery inspection method of the present invention. FIG. 2 is a flowchart of the second embodiment of the all-solid-state battery inspection method of the present invention. FIG. 3 is a graph schematically showing the time dependence of the voltage drop amounts ΔV1 and ΔV2 and their reference values. FIG. 4A is a graph schematically showing voltage characteristics with respect to SOC at the time of charging and discharging of a normal battery in which a fine short circuit does not occur, and FIG. It is a graph which shows typically the voltage characteristic with respect to SOC at the time of charge about the battery which carried out, and discharge.

First, an all-solid battery that is an inspection target of the inspection method of the present invention will be described.
The all solid state battery of the present invention includes one or more laminates of a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer. One or two or more of the laminated bodies are laminated together via a separator, for example, and accommodated in a case and sealed. The positive electrode layer, the negative electrode layer, and the solid electrolyte layer of the all-solid battery are not particularly limited as long as they are manufactured from materials having functions as the positive electrode, the negative electrode, and the solid electrolyte, respectively, and are known in the technical field. Things can be used. The positive electrode layer includes a positive electrode current collector and a positive electrode mixture layer formed thereon, and the negative electrode layer includes a negative electrode current collector and a negative electrode mixture layer formed thereon. The positive electrode mixture layer includes at least a positive electrode active material, and the negative electrode mixture layer includes at least a negative electrode active material. Examples of the positive electrode active material and the negative electrode active material include electrode active materials that can be used in all solid lithium secondary batteries. Examples of the electrode active material that can be used for the lithium secondary battery include lithium cobaltate (LiCoO ₂ ); lithium nickelate (LiNiO ₂ ); Li _{1 + x} Ni _1/3 Mn _1/3 Co _1/3 O ₂ (0 ≦ x ≦ 1); lithium manganate (LiMn ₂ O ₄ ); Li _{1 + x} Mn _2−xy M _y O ₄ (M is at least one selected from Al, Mg, Co, Fe, Ni and Zn) , 0 ≦ x ≦ 0.06, 0.03 ≦ y ≦ 0.15), a heteroelement-substituted Li—Mn spinel having a composition represented by: Lithium titanate (Li _x TiO _y , 0.36 ≦ x ≦ 2, 1.8 ≦ y ≦ 3); lithium metal phosphate (LiMPO ₄ , M is one or more selected from Fe, Mn, Co and Ni); vanadium oxide (V ₂ O ₅ ), molybdenum oxide (MoO ₃ ), etc. Transition money Oxides; titanium sulfide _(TiS 2); graphite, carbon materials such as hard carbon; lithium cobalt nitride (LiCoN); lithium silicon oxide _{(Li x Si y O z,} x + 4y-2z = 0); lithium metal (Li Lithium alloy (LiM; M is one or more selected from Sn, Si, Al, Ge, Sb, P, etc.); Lithium-storable intermetallic compound (Mg _x M; M is selected from Sn, Ge, and Sb) 1 or more, _or, N y Sb; N is an in, one or more selected from Cu and Mn); and derivatives thereof. Here, there is no clear distinction between each of the positive electrode active material and the negative electrode active material, and the charge / discharge potentials of the two types of compounds are compared. A battery having an arbitrary voltage can be formed by combining the illustrated materials as the negative electrode active material.

In addition to the positive electrode active material and the negative electrode active material, the positive electrode mixture layer and the negative electrode mixture layer are respectively solid electrolytes for the purpose of imparting ion conductivity, imparting conductivity, imparting flexibility, etc. to the electrode layer. Further, it may contain a conductive aid, a binder and the like.
The solid electrolyte is not particularly limited as long as it can impart ion conductivity to the positive electrode mixture layer, and examples thereof include those exemplified below as the solid electrolyte constituting the solid electrolyte layer. The binder is not particularly limited as long as flexibility can be imparted to the electrode layer, and examples thereof include those exemplified below as the binder constituting the solid electrolyte layer.
The conductive auxiliary agent is not particularly limited as long as it can impart electronic conductivity to the electrode layer, and examples thereof include those that can be used in lithium secondary batteries. Specific examples include conductive carbon materials such as acetylene black, ketjen black, VGCF (vapor-grown carbon fiber), and carbon nanotube.

  The ratio of each component which comprises a positive mix layer and a negative mix layer is not specifically limited. The thickness of the positive electrode mixture layer and the negative electrode mixture layer is not particularly limited. The thickness of the positive electrode mixture layer and the negative electrode mixture layer is preferably 0.1 μm or more and 1000 μm or less.

The solid electrolyte layer includes at least a solid electrolyte. As a solid electrolyte, what can be used for a lithium secondary battery is mentioned, for example. Specifically, as a solid electrolyte of a lithium secondary battery, Li ₂ O—B ₂ O ₃ —P ₂ O ₅ , Li ₂ O—SiO ₂ , Li ₂ O—B ₂ O ₃ , Li ₂ O—B ₂ Oxide-based solid electrolytes such as O ₃ —ZnO, Li ₂ S—SiS ₂ , LiI—Li ₂ S—SiS ₂ , LiI—Li ₂ S—P ₂ S ₅ , LiI—Li ₂ S—B ₂ S ₃ , _{Li 3 PO 4 -Li 2 S-} Si 2 S, Li 3 PO 4 -Li 2 S-SiS 2, LiPO 4 -Li 2 S-SiS, LiI-Li 2 S-P 2 O 5, LiI-Li 3 PO _{4 -P 2 S 5, Li 2} S-GeS 2, Li 2 S-Al 2 S 3, Li 2 S-P 2 S 5 ( e.g., Li ₂ S and _P 2 _{S 5} mass ratio of 50: 50 to 100: Mixing Li ₂ S and P ₂ S ₅ with 0, eg 70:30 And sulfide-based solid electrolytes.

  The solid electrolyte layer preferably contains a binder from the viewpoint of flexibility of the solid electrolyte layer. Examples of the binder include a fluorine resin such as polyvinylidene fluoride (PVDF) and a rubbery resin such as butadiene rubber (BR).

  In the solid electrolyte layer, the ratio of each component constituting the solid electrolyte layer is not particularly limited. The thickness of the solid electrolyte layer is not particularly limited. The solid electrolyte layer has a thickness of, for example, 0.1 μm to 1000 μm, preferably 0.1 μm to 300 μm.

The positive electrode current collector and the negative electrode current collector are not particularly limited as long as they are generally known to function as current collectors. Examples of the positive electrode current collector include, for example, stainless steel (SUS), nickel (Ni), chromium (Cr), gold (Au), platinum (Pt), aluminum (Al), iron (Fe), and titanium (Ti). And those manufactured from materials such as zinc (Zn). Examples of the negative electrode current collector are manufactured from materials such as stainless steel (SUS), copper (Cu), nickel (Ni), iron (Fe), titanium (Ti), cobalt (Co), and zinc (Zn). The thing which was done is mentioned. The shape of the positive electrode current collector and the negative electrode current collector can be appropriately selected according to the use of the all-solid battery, and can be, for example, a foil shape or a mesh shape. The thickness of the current collector can be changed according to the constituent material of the current collector, the intended use, and the like, and is not particularly limited. The thickness of the positive electrode current collector and the negative electrode current collector is typically
It is 6 μm or more and 30 μm or less.

  Said all-solid-state battery can have a positive electrode terminal, a negative electrode terminal, etc. which were connected to the separator, the positive electrode collector, and the negative electrode collector other than the member mentioned above. The material and shape of these members can be appropriately selected according to the use of the all solid state battery.

Hereinafter, an inspection method for an all solid state battery of the present invention will be described with reference to the drawings.
FIG. 1 is a flowchart of an embodiment of the all-solid-state battery inspection method of the present invention. The inspection method of the present invention is performed on an all-solid battery.
When the inspection method of the present invention is started, first, the all solid state battery is initially charged (step S11). When the all solid state battery is used without being restrained, the all solid state battery is initially charged without applying restraining pressure. When the all solid state battery is used in a state where a predetermined restraining pressure is applied, the all solid state battery is initially charged with the predetermined restraining pressure applied during use.
Next, in step S12, the all solid state battery is self-discharged, and the voltage drop amount ΔV1 due to self-discharge after the predetermined time has elapsed (that is, the voltage V ₀ measured before the self-discharge and the self-discharge after the predetermined time are measured). Difference V ₀ -V ₁ ) with respect to the voltage V1.
Next, in step S13, it is determined whether or not ΔV1 exceeds the first reference value.
When the voltage drop amount ΔV1 is equal to or less than the predetermined first reference value, it is determined that the fine short circuit has not occurred (step S14), and the inspection is terminated.
When the voltage drop amount ΔV1 exceeds the predetermined first reference value, a restraint pressure higher than the restraint pressure during use of the all solid state battery is applied to the all solid state battery (step S15).
Next, the all solid state battery is charged under a pressure exceeding the restraining pressure when using the all solid state battery (step S16).
Next, the all solid state battery is self-discharged, and the voltage drop amount ΔV2 due to self-discharge (that is, the difference V ₀ −V between the voltage V ₀ measured before the self-discharge and the voltage V1 measured after the self-discharge for a predetermined time). ₂ ) is obtained (step S17).
Next, in step S18, it is determined whether or not the voltage drop amount ΔV2 exceeds the second reference value. When the voltage drop amount ΔV2 is equal to or less than the predetermined second reference value, it is determined that the fine short circuit has not occurred (step S14), and the inspection is terminated.
If the voltage drop amount ΔV2 exceeds the predetermined second reference value, it is determined that the product is a defective product in which a fine short circuit has occurred (step S19), and the inspection is terminated.
According to the above-described first embodiment of the present invention, even if the voltage drop amount ΔV1 due to self-discharge exceeds the first reference value in step S13 for the inspected all-solid-state battery, the process proceeds to step S18. If it is determined that a fine short circuit has not occurred by comparing the voltage drop amount ΔV2 with the second reference value, the inspected all solid state battery is determined to be a non-defective product. In the first embodiment of the inspection method of the present invention, as described above, the step of determining whether or not the voltage drop amount ΔV1 exceeds a predetermined first reference value, and the voltage drop amount ΔV2 is a predetermined second value. By including the step of determining whether or not the reference value is exceeded, a fine short circuit can be detected with higher accuracy.

  The initial charging in step S11 and the charging in step S16 are performed until a predetermined voltage is reached. In step S11 and step S16, for example, in the case of an all-solid battery in which the positive electrode active material is made of lithium cobalt oxide and the negative electrode active material is made of natural graphite, charging is performed until the voltage reaches 4V. The charging voltage in step S11 and the charging voltage in step S16 are preferably the same voltage in order to detect a slight short circuit. When the all solid state battery is used without being restrained, the all solid state battery is initially charged without applying restraining pressure. When the all solid state battery is used in a state where a predetermined restraining pressure is applied, the all solid state battery is initially charged with the predetermined restraining pressure applied during use. The constraint pressure in step S11 is preferably 0 MPa to 15 MPa, and the constraint pressure in step S15 is preferably 10 MPa to 200 MPa. In the case of an all-solid-state battery, if a conductive foreign substance is present in the solid electrolyte layer or on the surfaces of the positive electrode layer and the negative electrode layer, a fine short circuit becomes noticeable and a self-discharge amount increases by applying a high restraint pressure.

  Examples of the method for applying the restraining pressure to the laminate of the all solid state battery include a mechanical pressurization method in which pressurization is performed using a mechanically generated pressure, and a pressurization is performed using a gas pressure. Although the gas pressurization method to perform is mentioned, it is not limited to these. Examples of the mechanical pressurizing method include a method of driving a motor and pressurizing in the stacking direction of the laminate through a ball screw, and a method of driving the motor and pressurizing in the stacking direction of the stack through hydraulic pressure. After pressurizing to a predetermined pressure, the energy consumption accompanying the drive of a motor can be suppressed to the minimum necessary by fixing an operation part with a mechanical stopper. Examples of the gas pressurizing method include a method of pressurizing the laminate from a gas cylinder through a pressurized gas. It is preferable that the restraining pressure is limited to a pressure that allows a fine short circuit inspection.

  The self-discharge in steps S12 and S16 is performed by leaving the all solid state battery at a predetermined temperature for a predetermined time. The self-discharge in steps S12 and S16 is preferably performed under the same ambient environmental conditions (for example, temperature, humidity, etc.). The self-discharge in steps S12 and S16 can be performed, for example, by leaving the all solid state battery at a temperature of 25 ° C. for 30 hours.

Next, with reference to FIG. 2, another embodiment (hereinafter referred to as “second embodiment”) of the all-solid-state battery inspection method of the present invention will be described.
When the inspection method is started, first, the all solid state battery is initially charged (step S21). The all solid state battery is initially charged with a predetermined restraint pressure applied during use.
Next, in step S22, the all-solid battery by self-discharge, the voltage drop [Delta] V1 (i.e. the voltage V1 measured after self-discharge of the self-discharge voltage V ₀ is measured before a predetermined time due to self-discharge The difference V ₀ -V ₁ ) is determined.
Next, in step S23, it is determined whether or not ΔV1 exceeds the first reference value.
When the voltage drop amount ΔV1 is equal to or less than the predetermined first reference value, it is determined that the fine short circuit has not occurred (step S24), and the inspection is terminated.
When the voltage drop amount ΔV1 exceeds a predetermined first reference value, next, charge / discharge capacity measurement is performed with a constant current-constant voltage (cccv: constant current-constant voltage), and the Coulomb efficiency E _CD (that is, Constant voltage (cv) discharge capacity / constant voltage (cv) charge capacity), constant current (cc) capacity drop amount ΔC1 (ie, constant current (cc) discharge capacity−initial constant current (cc) discharge capacity) and constant voltage (cv ) Capacity reduction amount ΔC2 (that is, constant voltage (cv) discharge capacity−initial constant voltage (cv) discharge capacity) is obtained (step S25).
Next, for the coulomb efficiency (E _CD ), constant current (cc) capacity reduction amount (ΔC1), and constant voltage (cv) capacity reduction amount (ΔC2) obtained in step S25, E _CD is less than a predetermined reference value. It is determined whether or not ΔC1 exceeds a predetermined first capacity reference value, or ΔC2 exceeds a predetermined second capacity reference value. If E _CD is less than the predetermined reference value, or if ΔC1 exceed the first capacitance criterion value of a predetermined, or the ΔC2 exceeds the second capacity reference value predetermined in the battery and defective products A determination is made (S27), and the inspection is terminated. In cases other than the above, the battery is determined to be non-defective (step S24), and the inspection ends.

Here, in the charge / discharge capacity measurement in step S25, first, constant current-constant voltage discharge is performed to a voltage of 0% charge state (SOC: State of Charge). Next, constant current / constant voltage charging is performed to a voltage of SOC 100%, and constant current-constant voltage discharging is performed again to SOC 0%. Coulomb efficiency E _CD , constant current capacity decrease amount ΔC1 and constant voltage capacity decrease amount ΔC2 are calculated from the value of the charge / discharge capacity. Note that the charge / discharge capacity measurement is not limited to the measurement in the range of SOC 0 to 100%. If the Coulomb efficiency E _CD , the constant current capacity decrease amount ΔC1 and the constant voltage capacity decrease amount ΔC2 can be calculated from the measurement results, the SOC 10 It can also be implemented in the range of% to 90% and other ranges.

  Here, “predetermined first reference value” for ΔV1 in the first and second embodiments of the inspection method of the present invention and “predetermined second reference value” for ΔV2 in the second embodiment. "Is a value set in advance as the amount of voltage drop to the extent that it is determined that a slight short circuit has occurred in the all-solid-state battery, corresponding to the predetermined times when ΔV1 and ΔV2 are measured.

Further, in the second embodiment of the inspection method of the present invention, the "predetermined reference value" for E _CD, which is a preset value as the allowable value of the leakage current due to the fine short circuit in the battery. The “predetermined first capacity reference value” for ΔC1 is a value set in advance as an allowable value for an increase in the internal resistance of the battery. The “predetermined second capacity reference value” for ΔC2 is a value set in advance as an allowable value for loss of Li ions. As a cause of ΔC1 exceeding the first capacity reference value, for example, deterioration of the solid electrolyte may be mentioned. As a cause of ΔC2 exceeding the second capacity reference value, for example, a reaction of LiC ₆ with moisture is cited. In the second embodiment of the inspection method of the present invention, as described above, the step of determining whether or not the voltage drop amount ΔV1 exceeds a predetermined first reference value, and the voltage drop amount ΔV2 is a predetermined second value. By including the step of determining whether or not the reference value is exceeded, a fine short circuit can be detected with higher accuracy. It is possible to determine with high accuracy whether there is a defect in the battery due to a micro short circuit or other causes such as deterioration of the solid electrolyte, reaction of LiC ₆ with moisture, and the like.

  FIG. 3 shows an example of a first reference value preset for the voltage drop amount ΔV1 due to self-discharge and a second reference value preset for the voltage drop amount ΔV2, in relation to ΔV1 and ΔV2. In this example, the first reference value and the second reference value are time-dependent, and the first reference value R1 (t) and the second reference value R2 (t) are respectively Curves (A) and (D) are shown as a function of time. When the battery to be inspected shows a discharge curve (B) of ΔV1 (t) ≦ R1 (t), it is determined that the battery is a non-defective product in which a fine short circuit has not occurred, and ΔV1 (t)> R1 (t ) In the discharge curve (C), it is determined that the battery is a defective product in which a fine short circuit has occurred. When the battery to be inspected shows a discharge curve (E) of ΔV2 (t) ≦ R2 (t), it is determined that the battery is a non-defective product with no slight short circuit, and ΔV2 (t)> R2 (t ) Of the discharge curve (F), it is determined that the battery is a defective product in which a fine short circuit has occurred. In addition, 1st reference value R1 (t) and 2nd reference value R2 (t) can be determined from the relationship of charge condition SOC previously calculated | required, time, battery capacity, and voltage. Since the first reference value R1 (t) and the second reference value R2 (t) change depending on factors such as the type of the positive electrode material and the negative electrode material and the capacity ratio between the positive electrode and the negative electrode, the first reference value R1 ( The shape of the curve of t) and the second reference value R2 (t) is not limited to that shown in FIG. However, the relationship of the second reference value R2 (t)> the first reference value R1 (t) is satisfied. This is because the thickness of the solid electrolyte layer when the above determination is made based on the second reference value R2 (t) is based on the first reference value R1 (t) due to an increase in the binding pressure of the battery. This is because the leakage current at the time of making the above determination based on the second reference value R2 (t) is larger than that based on the first reference value R1 (t). is there.

  FIG. 4A is a graph schematically showing voltage characteristics with respect to SOC at the time of charging and discharging of a normal battery in which a fine short circuit does not occur, and FIG. It is a graph which shows typically the voltage characteristic with respect to SOC at the time of charge about the battery which carried out, and discharge. As shown in FIG. 4 (b), when a slight short circuit occurs, a leakage current flows from the part of the short circuit, and the charged charge is lost, resulting in a decrease in charge / discharge efficiency. I know that

  The all-solid-state battery inspected by the inspection method of the present invention has high reliability and is useful as a power source for a motor mounted on a vehicle such as a hybrid vehicle or an electric vehicle.

Claims (2)

An inspection method for an all-solid battery,
(I) after charging the battery, obtaining a voltage drop ΔV1 due to self-discharge of the battery;
(Ii) a step of determining whether or not the voltage drop amount ΔV1 exceeds a predetermined first reference value;
(Iii) When the voltage drop amount ΔV1 exceeds a predetermined first reference value, the battery is charged under a pressure exceeding the binding pressure during use of the battery, and self-discharged to cause a voltage drop amount due to self-discharge. Obtaining ΔV2;
(Iv) determining whether or not the voltage drop amount ΔV2 exceeds a predetermined second reference value; and (v) when the voltage drop amount ΔV2 exceeds a predetermined second reference value, A process for determining a defective product,
A method for inspecting all solid state batteries. An inspection method for an all-solid battery,
(I) after charging the battery, obtaining a voltage drop ΔV1 due to self-discharge of the battery;
(Ii) a step of determining whether or not the voltage drop amount ΔV1 exceeds a predetermined first reference value;
(Iii) When the voltage drop amount ΔV1 exceeds a predetermined first reference value, charge / discharge capacity measurement is performed with respect to the battery at a constant current and constant voltage, and the coulomb efficiency, the constant current capacity decrease amount and the constant voltage capacity are measured. A process for determining the amount of decrease,
(Iv) (a) Whether the coulomb efficiency obtained in step (iii) is less than a predetermined reference value, or (b) the constant current capacity decrease amount obtained in step (iii) is a predetermined first (C) determining whether or not the constant voltage capacity reduction amount obtained in step (iii) exceeds a predetermined second capacity reference value; and (v) ) When the coulomb efficiency is less than a predetermined reference value, or when the constant current capacity decrease amount exceeds a predetermined first capacity reference value, or the constant voltage capacity decrease amount is equal to a predetermined second capacity reference value. A process of determining the battery as a defective product when exceeding,
A method for inspecting all solid state batteries.

Images