KR20220145501A - Secondary battery to cause defects and Method for evaluating the characteristics of the Secondary battery - Google Patents

Abstract

A purpose of the present invention is to provide a secondary battery for causing a defect and a method for evaluating characteristics of the secondary battery, wherein aspects of the battery due to deterioration and ignition of the battery can be observed in detail according to a defect factor without deformation of the battery. To this end, the secondary battery for causing a defect according to the present invention comprises: an electrode assembly including a negative electrode, a positive electrode, and a separator laminated between the negative electrode and the positive electrode; an external material surrounding the electrode assembly; and a capsule accommodating a defect factor therein and disposed inside the electrode assembly or inside the external material, wherein the capsule is opened by a physical stimulus.

Description

Secondary battery to cause defects and Method for evaluating the characteristics of the Secondary battery

The present invention relates to a secondary battery, and more particularly, to a secondary battery for inducing a defect capable of simulating a defect of the battery including a factor causing the defect by being physically opened.

A secondary battery is a battery that converts chemical energy into electrical energy to supply power to an external circuit, and when discharged, receives external power to convert electrical energy into chemical energy to store electricity. .

As technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source has increased, and lithium secondary batteries, which are attracting attention as a next-generation power source among rechargeable secondary batteries, have high energy density, have no memory effect, and even when not in use. The degree of natural discharge is small and very light, so it is widely used in portable electronic devices such as laptops, cameras, and cell phones. In addition, by using the characteristic of high energy density, the frequency of its use is gradually increasing in the defense industry, automation system, and automobile and aviation industries, and in particular, it is widely used as a motor driving source for electric and hybrid vehicles.

With the recent growth of the electric vehicle and energy storage system (ESS) market, reliability and safety issues of secondary batteries are becoming more important. Therefore, it is required to identify the cause of safety accidents such as ignition of a battery and fire of an energy storage device. In order to identify various causes of ignition, analysis of deteriorated and ignited batteries and electrochemical evaluation of similar batteries are performed.

In order to solve the above problems, referring to Korean Patent Application Laid-Open No. 10-2019-0088763, a lithium secondary battery including a conventional short-circuit inducing device as shown in FIG. The short-circuit inducing device includes a positive electrode active material layer 10 , a conductive paste layer 20 , and a separator 50 positioned between the positive electrode active material layer 10 and the conductive paste layer 20 , the positive electrode active material layer 10 and It includes a first wax layer 40 positioned between the separator 50 and a second wax layer 40 positioned between the conductive paste layer 20 and the separator 50 , and a metal foil part 60 in the separator 50 . ) is inserted and the temperature inside the battery exceeds 60 degrees Celsius while driving the battery, the first and second wax layers 30 and 40 are liquefied and flowed down. Accordingly, the positive electrode active material layer 10 and the conductive paste layer Since the metal foil portion 60 between the 20 is in direct contact with the positive electrode active material layer 10 and the conductive paste layer 20 , a current may flow through the metal foil portion 60 to cause an internal short.

However, in the prior art, only the thermal runaway pattern of the battery can be observed, and since the battery is physically damaged after thermal runaway, it is difficult to directly analyze the phenomenon inside the battery due to the defect.

Republic of Korea Patent Publication No. 10-2019-0088763 (published on July 29, 2019)

The present invention has been devised to solve the above problems, and it is possible to observe in detail the aspect of the battery due to the deterioration and ignition of the battery according to the defect factor without deformation of the battery and the characteristics of the secondary battery and the secondary battery for inducing a defect The purpose is to provide an evaluation method.

The secondary battery for inducing a defect according to the present invention includes an electrode assembly including a negative electrode, a positive electrode, and a separator laminated between the negative electrode and the positive electrode, a packaging material surrounding the electrode assembly, and a defect factor accommodated therein, and the electrode assembly is inside the electrode assembly Alternatively, including a capsule disposed inside the exterior material, the capsule may be characterized in that it is opened by a physical stimulus.

Furthermore, the electrode assembly may further include a perforation formed in at least one of the negative electrode, the separator, and the positive electrode, and the capsule may be inserted into the perforation.

In this case, the perforation may be formed over the negative electrode and the separator, the separator and the positive electrode, or the negative electrode, the separator, and all of the positive electrode.

Furthermore, the electrode assembly further includes a negative electrode tab connected to the negative electrode and a positive electrode tab connected to the positive electrode, and the capsule is located between a region where the negative electrode and the negative electrode tab overlap each other and the exterior material, the positive electrode and the The positive electrode tab may be disposed on at least one of an overlapping region and the exterior material.

In addition, the capsule may be disposed in an excess space between the outer side of the electrode assembly and the exterior material.

In addition, the defect factor is a solid, water, hydrogen fluoride (HF), metal ion, Dimethyl Ether, Triphenyl Phosphate, vinylen carbonate, Fluorinated carbonate, Lithium Difluorophosphate made of any one of deteriorated electrode particles, metal particles, lithium dendrite, and lithium powder. Any one or more selected from the group consisting of an electrolyte containing high concentration of electrolyte additives such as sodium bicarbonate, potassium hydrogen carbonate, and ammonium phosphate, fire retardants, gas generators, and interfacial stabilizers. It may consist of at least one of an electrolyte, an electrolyte having a lower concentration than the electrolyte contained in the electrode assembly, a liquid consisting of any one of an electrolyte having a higher concentration than the electrolyte contained in the electrode assembly, and a gas consisting of any one of hydrogen, methane, ethane, and carbon dioxide.

Further, the capsule is PVdF (Polyvinylidene fluoride), SBR (Styrene-butadiene), polyimide (Polyimide), polyisobutylene (Polyisobutylene), carboxymethyl cellulose sodium (Sodium Carboxymethyl Cellulose), polyacrylic acid (Polyacrylic Acid), It may include a capsule exterior material of any one of polyvinyl alcohol and wax.

Furthermore, the physical stimulus for opening the capsule may be applied to at least one of a certain pressure, a certain temperature, a magnetic field of a certain size, an electromagnetic wave of a certain intensity, and X-rays of a certain intensity.

In the method for evaluating characteristics of a secondary battery according to the present invention, (1) an electrode assembly including a negative electrode, a positive electrode, and a separator laminated between the negative electrode and the positive electrode, a packaging material surrounding the electrode assembly, and a defect factor are accommodated therein; , providing a secondary battery including a capsule disposed inside the electrode assembly or inside the exterior material, (2) applying a physical stimulus capable of releasing a defect factor by opening the capsule to the secondary battery; 3) It may be characterized in that it comprises the step of analyzing the behavior of the secondary battery in which the defect has occurred.

In this case, in the step (2), at least one of a pressure, a temperature, a magnetic field, an electromagnetic wave, and an X-ray may be applied to the capsule.

In addition, the step (3) may include at least one of a voltage profile change during charging and discharging of the secondary battery due to the release of the defect factor, a change in temperature at the part where the defect factor is emitted, deterioration, ignition, and expansion of the thickness of the secondary battery compared to before the release of the defect factor. At least one behavior may be analyzed during analysis before battery disassembly, including one, and analysis after battery disassembly, including at least one of positive and negative surface change observation, surface composition change observation, crystal structure change, and electrode binding force change.

In the secondary battery for inducing a defect according to the present invention through the configuration as described above, the capsule disposed inside the electrode assembly or the casing surrounding the electrode assembly is opened and the defect factor is leaked, so that the deterioration of the battery and the ignition association are reduced. It can be observed in situ where it was placed.

In addition, since the capsule is installed in the battery, deterioration and ignition of the battery due to defect factors can be checked without physical damage or deformation of the battery from the outside, and the installation position can be freely adjusted by adjusting the size of the capsule. Deterioration and ignition phenomena can be confirmed at various locations.

In addition, since the type and content of the defect factor in the capsule can be freely adjusted, the behavior of the battery can be analyzed in various environments for the defect factor, and a database can be constructed for deterioration and ignition patterns.

In addition, since the opening time of the capsule can be adjusted, the electrochemical signal of the defect factor according to the battery driving conditions can be directly observed, and the defect factor is expressed without deformation of the battery, so there is an effect that analysis after battery deterioration is possible. .

1 is a cross-sectional view of a lithium secondary battery including a conventional short-circuit inducing device;
2 is a front view of a secondary battery for inducing a defect according to the present invention;
3 is an exploded view of an electrode assembly according to the present invention;
Figure 4 is an embodiment of the capsule opening according to the present invention
5 is a cross-sectional view of first to third embodiments of a secondary battery for inducing a defect according to the present invention;
6 is a perspective view of a fourth embodiment of a secondary battery for inducing a defect according to the present invention;
7 is a perspective view of a fifth embodiment of a secondary battery for inducing defects according to the present invention;
8 is a flowchart of a method for evaluating characteristics of a secondary battery according to the present invention;
9 is a voltage profile before and after expressing the defect factor according to Example 1
10 is a photograph confirming that the battery swells due to the generation of gas, which is an electrolyte side reactant, after the defect factors of Comparative Examples 1 and 2 are expressed;

Hereinafter, the technical idea of the present invention will be described in more detail with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that it can be defined, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

Therefore, the configuration shown in the embodiments and drawings described in the present specification is merely the most preferred embodiment of the present invention and does not represent all of the technical spirit of the present invention, so at the time of the present application, various It should be understood that there may be variations.

Hereinafter, the technical idea of the present invention will be described in more detail with reference to the accompanying drawings. Since the accompanying drawings are merely examples shown to explain the technical idea of the present invention in more detail, the technical idea of the present invention is not limited to the form of the accompanying drawings.

2 to 4 , the secondary battery 1000 for inducing defects according to the present invention includes a negative electrode 110 , a positive electrode 120 , and a separator stacked between the negative electrode 110 and the positive electrode 120 ( 130) including an electrode assembly 100, a casing 200 surrounding the electrode assembly 100, and a defect factor 310 accommodated therein, inside the electrode assembly 100 or inside the casing 200 It may include a capsule 300 to be disposed, and the capsule 300 may be characterized in that it is opened by a physical stimulus.

3 , the electrode assembly 100 is formed by stacking a separator 130 between the negative electrode 110 and the positive electrode 120 .

The casing 200 surrounds the entire outer surface of the electrode assembly 100 , and the electrode assembly 100 is packaged in the casing 200 to maintain a stacked state.

As shown in FIG. 4 , the defect factor 310 is accommodated in the capsule 300 . The capsule 300 is disposed inside the electrode assembly 100 or inside the casing 200 , and the capsule 300 is opened by a physical stimulus and the defect factor 310 inside the capsule 300 . flows into the electrode assembly 100 or the exterior material 200 .

The capsule 300 may be disposed inside the electrode assembly 100 , may be disposed between the electrode assembly 100 and the casing 200 , and between the upper and lower surfaces of the casing 200 . may be placed.

In the secondary battery 1000 for inducing defects according to the present invention through the configuration as described above, the electrode assembly 100 or the capsule 300 disposed on the inside of the casing 200 surrounding the electrode assembly 100 is opened and there is a defect. As the factor 310 flows out, deterioration and ignition association of the battery 1000 can be observed in-situ where the capsule 300 is disposed.

In addition, the defect factor 310 is a solid, water, hydrogen fluoride (HF), metal ion, Dimethyl Ether, Triphenyl Phosphate, vinylen carbonate, Fluorinated carbonate made of any one of deteriorated electrode particles, metal particles, lithium dendrite, and lithium powder. Any one or more selected from the group consisting of an electrolyte containing a high concentration of electrolyte additives such as , lithium difluorophosphate, a fire extinguishing material containing any one or more of sodium hydrogen carbonate, potassium hydrogen carbonate, and ammonium phosphate, a flame retardant, a gas generator, and an interfacial stabilizer This contained electrolyte, an electrolyte having a lower concentration than the electrolyte contained in the electrode assembly 100, a liquid consisting of any one of an electrolyte having a higher concentration than the electrolyte contained in the electrode assembly 100, and hydrogen, methane, ethane, and carbon dioxide It may consist of at least one of the gases consisting of one.

That is, the defect factor 310 may be made of at least one of solid, liquid, and gas, and may be accommodated in the capsule 300 in combination of the defect factors 310 having different material types.

In addition, the capsule 300 is PVdF (Polyvinylidene fluoride), SBR (Styrene-butadiene), polyimide (Polyimide), polyisobutylene (Polyisobutylene), carboxymethyl cellulose sodium (Sodium Carboxymethyl Cellulose), polyacrylic acid (Polyacrylic Acid) ), polyvinyl alcohol (Polyvinyl Alcohol), and any one of a wax capsule 300 may include the exterior material (200).

The capsule 300 exterior material 200 is a material constituting the capsule 300 may be formed of any one of the above materials.

In addition, the physical stimulus for opening the capsule 300 may be applied to at least one of a certain pressure, a certain temperature, a magnetic field of a certain size, an electromagnetic wave of a certain intensity, and X-rays of a certain intensity.

That is, the capsule 300 is opened by stimulation of any one of a certain pressure, a certain temperature, a magnetic field of a certain size, an electromagnetic wave of a certain intensity, or an X-ray of a certain intensity, and the defect factor 310 is the capsule 300 . can leak out.

In addition, the shape of the capsule 300 may be a cylindrical shape, a capsule 300 type, a rectangle, a sphere, a cuboid, or a micellar shape, but is not limited thereto, and any shape can be applied as long as it can be developed by a certain physical stimulus. It is possible.

Referring to FIG. 5A , the electrode assembly 100 further includes a perforation 140 formed in at least one of the negative electrode 110 , the separator 130 , and the positive electrode 120 , The capsule 300 may be inserted into the perforation 140 . Since the capsule 300 has to store the defect factor 310 therein, it has an internal accommodating space and forms a certain volume. Accordingly, when the capsule 300 is disposed inside the electrode assembly 100 or inside the casing 200 , the overall size or thickness of the secondary battery increases. Accordingly, the perforation 140 is formed in at least one of the negative electrode 110 , the separator 130 , and the positive electrode 120 , and the capsule 300 is inserted into the perforation 140 . An increase in overall size or thickness can be prevented.

The perforation 140 may be formed in only one of the negative electrode 110 , the separator 130 , and the positive electrode 120 .

In addition, the perforation 140 is formed over the cathode 110 and the separator 130 , the separator 130 and the anode 120 , or the cathode 110 , the separator 130 . ), may be formed over all of the anode 120 .

A plurality of the perforations 140 may be formed at different positions, and the perforations 140 may be any one of the separator 130 or the separator 130 and the cathode 110 or the anode 120 . When formed over, it is preferable that the capsule 300 is custom-inserted into the perforation 140 so that the anode 120 and the cathode 110 do not come into contact with each other.

Referring to FIG. 5B , the capsule 300 may be disposed on a side surface of the electrode assembly 100 in which the negative electrode 110 , the separator 130 , and the positive electrode 120 are stacked. The outer peripheral surface of the capsule 300 is preferably formed in contact with at least one of the negative electrode 110 , the separator 130 , and the positive electrode 120 .

Referring to FIG. 5C , the capsule 300 is disposed between the negative electrode 110 and the separator 130 in a state in which the negative electrode 110 , the separator 130 and the positive electrode 120 are stacked. It may be stacked between the separator 130 and the anode 120 .

Referring to FIG. 6 , the electrode assembly 100 further includes a negative electrode 110 tab connected to the negative electrode 110 and a positive electrode 120 tab connected to the positive electrode 120 , and the capsule 300 . is between the area where the negative electrode 110 and the negative electrode 110 tab overlap each other and the exterior material 200 , and between the area where the positive electrode 120 and the positive electrode 120 tab overlap and the exterior material 200 . It may be disposed on at least one or more.

That is, in a state in which the capsule 300 is disposed at a point where the negative electrode 110 tab and the negative electrode 110 are connected or the positive electrode 120 tab and the positive electrode 120 are connected, the exterior material 200 ) may surround the electrode assembly 100 and the capsule 300 .

Referring to FIG. 7 , the capsule 300 may be disposed in an excess space between the outside of the electrode assembly 100 and the exterior material 200 . The redundant space refers to a region where the electrode assembly 100 is not formed when the exterior material 200 surrounds the electrode assembly 100, and the capsule 300 disposed in the redundant space has at least a part of it. It may be in contact with the electrode assembly 100 or may not be in contact with the electrode assembly 100 at all.

Referring to FIG. 8 , the method for evaluating characteristics of a secondary battery according to the present invention includes (1) a negative electrode 110 , a positive electrode 120 , and a separator 130 stacked between the negative electrode 110 and the positive electrode 120 . An electrode assembly including a 100, the casing 200 surrounding the electrode assembly 100, and the defect factor 310 is accommodated therein, the electrode assembly 100 is disposed inside or inside the casing 200 providing a secondary battery 1000 including a capsule 300; (2) applying a physical stimulus capable of releasing the defect factor 310 by opening the capsule 300 to the secondary battery 1000 and (3) analyzing the behavior of the secondary battery 1000 in which the defect has occurred.

At this time, the step (2) is characterized in that at least one or more physical stimulation of pressure, temperature, magnetic field, electromagnetic waves and X-rays is applied to the capsule 300 .

In addition, in step (3), a voltage profile change during charging and discharging of the secondary battery 1000 due to the release of the defect factor 310 , a temperature change at a portion where the defect factor 310 is emitted, deterioration, ignition, and a defect factor (310) Analysis before battery dismantling, including at least one of the thickness expansion of the secondary battery 1000 compared to before release, and observation of changes in the surface of the positive electrode 120 and the negative electrode 110, observation of changes in surface composition, changes in crystal structure, and changes in electrode binding force At least one behavior may be analyzed during analysis after disassembling the battery including at least one.

That is, in the method for evaluating the characteristics of a secondary battery according to the present invention, after applying a physical stimulus to the capsule 300 , the behavior before or after disassembling the secondary battery 1000 including the capsule can be analyzed.

Referring to FIGS. 9 to 10 , the experimental process and experimental results, including the characteristics of the secondary battery 1000 for inducing defects and the characteristic evaluation method of the secondary battery according to the present invention, are as follows.

In the electrode assembly 100 of Examples 1 and 2, the positive electrode 120 is a transition metal oxide Li (Ni _0.8 Mn _0.1 Co _0.1 )O ₂ (L&F, Korea) 93 wt%, a conductive material (Super P Li ^ㄾ , Imerys) ) 4% by weight, polyvinylidene fluoride (PVdF, KF-1300, Kureha) 3% by weight, the anode 110 is graphite 92% by weight, conductive material (Super P Li ^ㄾ , Imerys) 4% by weight, It was designed with 4 wt% CMC/SBR. Ethylene carbonate/Ethylmethyl carbonate (volume ratio 3/7) (ENCHEM, Korea) containing 1.15 M of LiPF ₆ , a lithium salt, is used as the electrolyte, and PE is used as the separator 130. did.

(Example 1)

In Example 1, after the capsule 300 of the defect factor 310 containing an electrolyte having a high concentration of HF is positioned between the positive electrode 120 and the separator 130, and a predetermined pressure is applied, the voltage profile of the secondary battery is A changed to B. As the defect factor 310 HF was expressed, an abnormal signal was observed in the discharge section due to decomposition of lithium salt / solvent and formation of side reaction products, and a thick film was formed on the positive electrode 120 / negative electrode 110 to increase the resistance in the battery It was confirmed that the CV section was lengthened due to

In addition, after 20 cycles from the expression of the defect factor 310, it was observed that the thickness of the battery increased by about 2 times compared to the conventional one. In particular, when the cell expressing the defect factor 310 was driven at a high temperature, Also, it was confirmed that the capacity retention rate was significantly reduced.

When the lithium content of the electrolyte was quantitatively analyzed by disassembling the battery after operation, it was confirmed that about 25% of lithium was consumed compared to the existing one, and it could be determined that this was due to lithium salt decomposition and side reactions caused by the expression of the defect factor 310 . .

(Example 2)

Referring to FIG. 10 , Comparative Example 1 is a secondary battery manufactured based on the same battery information as in Example 2 without a capsule containing a defect factor in the secondary battery, and in Example 2, transition metal ions (M ⁴⁺ , M= After the defect factor 310 capsule 300 containing the electrolyte containing Mn, Ni) was positioned outside the jelly roll including the electrode, a certain pressure was applied.

As the electrolyte defect factor 310 containing transition metal ions is expressed, it is expected that a resistance layer of MF ₂ is made in the positive electrode 120, and eluted and electrodeposited as a metal in the negative electrode 110, resulting in an increase in battery resistance and A decrease in capacity was observed in the voltage profile. In addition, after 20 cycles from the expression of the defect factor 310 as a starting point, it was observed that the thickness of the battery increased by about 3.5 times compared to the conventional one as shown in FIG. 10 .

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention as claimed in the claims.

1000: secondary battery for inducing defects
100: electrode assembly 110: cathode
111: negative electrode tab 120: positive electrode
121: positive electrode tab 130: separator
140: perforation
200: exterior material
300: capsule 310: defect factor

Claims (11)

an electrode assembly including a negative electrode, a positive electrode, and a separator laminated between the negative electrode and the positive electrode;
an exterior material surrounding the electrode assembly; and
A capsule having a defect factor accommodated therein and disposed inside the electrode assembly or inside the casing;
The secondary battery for inducing defects, characterized in that the capsule is opened by a physical stimulus.
The method of claim 1,
The electrode assembly,
Further comprising; a hole formed in at least one of the negative electrode, the separator, and the positive electrode;
A secondary battery for inducing a defect in which the capsule is inserted into the perforation.
3. The method of claim 2,
The hole is
A secondary battery for inducing defects formed over the negative electrode and the separator, formed across the separator and the positive electrode, or formed across all of the negative electrode, the separator, and the positive electrode.
The method of claim 1,
The electrode assembly,
a negative electrode tab connected to the negative electrode; and
It further includes; a positive electrode tab connected to the positive electrode;
The capsule is
The secondary battery for inducing defects is disposed in at least one of a region where the negative electrode and the negative electrode tab overlap each other and the case material, and between an area where the positive electrode and the positive electrode tab overlap each other and the case material.
The method of claim 1,
The capsule is
A secondary battery for inducing defects disposed in an excess space between the outer side of the electrode assembly and the exterior material.
The method of claim 1,
The defect factor is
A solid consisting of any one of deteriorated electrode particles, metal particles, lithium dendrites, and lithium powder,
Any one or more of water, hydrogen fluoride (HF), metal ions, dimethyl ether, triphenyl phosphate, vinylen carbonate, fluorinated carbonate, lithium difluorophosphate, electrolytes containing high concentrations of electrolyte additives, sodium bicarbonate, potassium hydrogen carbonate, and ammonium phosphate An electrolyte containing at least one selected from the group consisting of a fire extinguishing material, a flame retardant, a gas generator, and an interfacial stabilizer containing a liquid consisting of any one of, and
A secondary battery for inducing defects consisting of at least one of a gas consisting of any one of hydrogen, methane, ethane, and carbon dioxide.
The method of claim 1,
The capsule is
PVdF (Polyvinylidene fluoride), SBR (Styrene-butadiene), Polyimide, Polyisobutylene, Sodium Carboxymethyl Cellulose, Polyacrylic Acid, Polyvinyl Alcohol ) and a secondary battery for inducing defects including any one of the capsule exterior materials of wax.
The method of claim 1,
The physical stimulus to open the capsule is,
A secondary battery for inducing defects to which at least one of a certain pressure, a certain temperature, a magnetic field of a certain size, an electromagnetic wave of a certain intensity, and X-rays of a certain intensity is applied.
(1) an electrode assembly including a negative electrode, a positive electrode, and a separator laminated between the negative electrode and the positive electrode, a packaging material surrounding the electrode assembly, and a defect factor accommodated therein, and disposed inside the electrode assembly or inside the exterior material providing a secondary battery including a capsule;
(2) applying a physical stimulus capable of releasing a defect factor by opening the capsule to the secondary battery; and
(3) analyzing the behavior of the defective secondary battery;
A method for evaluating characteristics of a secondary battery comprising a.
10. The method of claim 9,
The step (2) is,
A method for evaluating characteristics of a secondary battery by applying at least one physical stimulus of pressure, temperature, magnetic field, electromagnetic wave, and X-ray to the capsule.
10. The method of claim 9,
The step (3) is,
of the secondary battery due to the release of the defect factor
Analysis before battery disassembly, including at least one of voltage profile change during charging and discharging, temperature change at the site where the defect factor is emitted, deterioration, ignition, and expansion of the thickness of the secondary battery compared to before the release of the defect factor, and
Analysis after battery disassembly, including at least one of a change in the surface of anode and anode, observation of a change in surface composition, a change in crystal structure, and a change in electrode binding force
A characteristic evaluation method of a secondary battery for analyzing the behavior of at least one of

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