JP6944653B2 - Power storage element - Google Patents

Description

The present invention relates to a power storage element provided with a current cutoff mechanism that cuts off a conduction path connecting an external terminal and an electrode body.

Conventionally, a battery having a current cutoff mechanism that cuts off the current when the internal pressure of the battery rises due to overcharging or the like has been known (see Patent Document 1). The specific configuration of this battery is as follows.

In the battery, the spiral electrode body is housed in the outer can, and the opening of the outer can is sealed by the sealing plate. Further, it is provided with an external positive electrode terminal and an external negative electrode terminal protruding from the sealing plate to the outside of the battery. A current collector tab member is connected to the positive electrode current collector plate group protruding from one end surface of the electrode body. This positive electrode current collector group is a bundle of a plurality of positive electrode current collector plates protruding from one end surface of the electrode body. As shown in FIG. 14, the external positive electrode terminal 101 has a gasket 102, an insulating member 104, and a sealing body lead 105 fitted to the sealing plate 103. The external positive electrode terminal 101 and the sealing body lead 105 are electrically connected. The sealing body lead 105 and the diaphragm 106 are connected so as to maintain the airtightness of the connecting portion, whereby the diaphragm 106 and the external positive electrode terminal 101 are electrically connected. The central portion of the metal thin film 108 is electrically connected to the central portion of the inner surface of the battery of the diaphragm 106. Further, the peripheral portion of the metal thin film 108 is attached so as to cover the through hole 109c provided in the current collecting tab member 109 located below the diaphragm 106. Further, a pressure relief hole 101a is formed in the external positive electrode terminal 101.

In the above battery, when the internal pressure of the battery is normal, a current flows from the current collecting tab member 109 to the diaphragm 106 via the metal thin film 108. On the other hand, when the internal pressure of the battery rises due to overcharging of the battery 100 or the like, as shown in FIG. 15, the central portion of the diaphragm 106 rises to the outside of the battery, and the metal thin film 108 connected to the central portion rises and breaks so as to be torn off. Then, the current from the current collecting tab member 109 to the diaphragm 106 is cut off. This prevents further charging of the battery 100 when it is overcharged.

In recent years, due to the usage situation of a battery in which a lot of charging and discharging are repeated, an amount of electrolytic solution larger than the amount that can be held by the spiral electrode body is injected into the outer can. In this case, the electrolytic solution is collected at the bottom of the outer can in a state where a part of the spiral electrode body is immersed. In this state, for example, as shown in FIG. 16, when the battery 100 is arranged with the surface of the sealing plate 103 protruding from the external positive electrode terminal 101 and the external negative electrode terminal 110 facing sideways, the internal pressure of the battery is applied. The diaphragm 106 (pressure receiving portion) is immersed in the electrolytic solution (surplus electrolytic solution) accumulated in the outer can 111.

Liquids such as electrolytes are more viscous and incompressible than gases. Therefore, for example, when the internal pressure of the battery rises due to overcharging during charging of the battery 100, if the diaphragm 106 is immersed in the excess electrolyte, the amount of displacement is smaller than that in the case of being in the gas, so that the current is cut off. The mechanism 112 may not function effectively, or it may not cut off the current until the internal pressure is higher than when it is in the gas. Moreover, in the battery 100, when the spiral electrode body 113 is immersed in the electrolytic solution and is overcharged (a state in which the potential exceeds the normal use range), gas is likely to be generated, so that the internal pressure of the battery becomes a set value. If the current is not cut off accurately at that time, the internal pressure of the battery may greatly exceed the set value (a value at which the current is cut off when the diaphragm (pressure receiving portion) 106 of the current cutoff mechanism 112 is in the gas).

Japanese Patent No. 5084205

Therefore, an object of the present embodiment is to provide a power storage element capable of accurately preventing overcharging.

The power storage element of this embodiment is
With electrolyte
An electrode body having an electrode containing an active material layer and
A case for accommodating the electrolytic solution and the electrode body inside, and
In the case, the external terminals arranged on the outer surface of the wall portion that spreads out in a plane,
It has a pressure receiving portion arranged inside the case, and includes a current blocking mechanism that cuts off a conduction path connecting the external terminal and the electrode body when the pressure receiving portion receives a pressure equal to or higher than a predetermined value. ,
In the first posture in which the outer surface of the wall portion faces upward and the second posture in which the outer surface of the wall portion faces in the horizontal direction, the electrolytic solution accumulated inside the case comes into contact with the active material layer and the pressure receiving portion. Is located above the accumulated electrolyte.

According to this configuration, if the power storage elements are arranged so that the case is in the first posture and the second posture, the active material layer is not held by the electrode body and is accumulated in the case (surplus). Since the pressure receiving part is located above the electrolyte stored inside the case even if it is in contact with the electrolyte), the current cutoff mechanism is accurate when overcharged, that is, when the internal pressure of the case reaches the set value. It operates well, which can accurately prevent overcharging of the power storage element.

In the power storage element,
An overcharge inhibitor that generates gas when in contact with the active material layer of the electrode body in an overcharged state and is added to the electrolytic solution may be provided.

According to this configuration, more gas is generated inside the case during overcharging, so that the internal pressure of the case rises sufficiently during overcharging, so that the current cutoff mechanism operates more accurately. Overcharging of the power storage element can be prevented more accurately. In the present application, the overcharged state is a state in which the potential of the power storage element exceeds the range of normal use.

Further, in the power storage element,
The active material layer has a positive electrode active material layer and a negative electrode active material layer.
The electrode body has a positive electrode including the positive electrode active material layer and a negative electrode including the negative electrode active material layer.
The pair of external terminals has a positive electrode external terminal conducting with the positive electrode and a negative electrode external terminal conducting with the negative electrode.
When the case is in the first posture and the second posture, the electrolytic solution accumulated inside the case may come into contact with the positive electrode active material layer.

In the power storage element, the amount of overcharge when the positive electrode active material layer is in contact with the electrolytic solution is larger than that when the negative electrode active material layer is overcharged when the negative electrode active material layer is in contact with the electrolytic solution. Gas is generated. Therefore, according to the above configuration, more gas is generated inside the case during overcharging than in the case where the negative electrode active material layer is in contact with the electrolytic solution in the first posture and the second posture. As a result, the current cutoff mechanism operates more accurately at the time of overcharging, and as a result, overcharging of the power storage element can be prevented more accurately.

in this case,
It is preferable that the current cutoff mechanism cuts off the conduction path connecting the positive electrode external terminal and the positive electrode of the electrode body.

Since gas is likely to be generated on the positive electrode side of the electrode body during overcharging, the current cutoff mechanism is arranged at a position close to the positive electrode (the conduction path connecting the external terminal of the positive electrode and the positive electrode of the electrode body) to overcharge. (Specifically, the response to an increase in the internal pressure due to the gas generated during overcharging) is improved, and as a result, overcharging of the power storage element can be prevented more accurately.

Further, the power storage element of this embodiment is
With electrolyte
An electrode body having an electrode containing an active material layer and
A case for accommodating the electrolytic solution and the electrode body inside, and
In the case, the external terminals arranged on the outer surface of the wall portion that spreads out in a plane,
It has a pressure receiving portion arranged inside the case, and includes a current blocking mechanism that cuts off a conduction path connecting the external terminal and the electrode body when the pressure receiving portion receives a pressure equal to or higher than a predetermined value. ,
The first posture in which the outer surface of the wall portion faces upward, the second posture in which the outer surface of the wall portion faces in the horizontal direction, and the direction in which the outer surface of the wall portion faces in the first posture to the second posture. In any of the third postures facing each direction up to, the electrolytic solution accumulated inside the case is in contact with the active material layer, and the pressure receiving portion is above the accumulated electrolytic solution. To position.

If the power storage elements are arranged so that the case is in the first posture, the second posture, and the third posture, the active material layer is not held by the electrode body and is accumulated inside the case (surplus electrolysis). Even if it is in contact with the liquid), the pressure receiving part is located above the electrolyte stored inside the case, so the current cutoff mechanism operates accurately when overcharging, thereby preventing overcharging of the power storage element. can do.

From the above, according to the present embodiment, it is possible to provide a power storage element that accurately prevents overcharging.

FIG. 1 is a perspective view of a power storage element according to the present embodiment. FIG. 2 is an exploded perspective view of the power storage element. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. FIG. 4 is a diagram for explaining an electrode body of the power storage element. FIG. 5 is an enlarged view of the periphery of the negative electrode external terminal in FIG. FIG. 6 is an enlarged view of the periphery of the positive electrode external terminal in FIG. FIG. 7 is an enlarged view of the periphery of the positive electrode external terminal in FIG. FIG. 8 is an exploded perspective view of the periphery of the positive electrode external terminal. FIG. 9 is a cross-sectional view of the external terminal in a state before being assembled to the case. FIG. 10 is a schematic view showing the first posture of the power storage element. FIG. 11 is a schematic view showing an example of the second posture of the power storage element. FIG. 12 is a schematic view showing an example of the third posture of the power storage element. FIG. 13 is a perspective view of a power storage device including the power storage element. FIG. 14 is an enlarged cross-sectional view for explaining a current cutoff mechanism in a conventional battery. FIG. 15 is an enlarged cross-sectional view for explaining a current cutoff mechanism in a conventional battery. FIG. 16 is a schematic view showing the relationship between the current cutoff mechanism and the liquid level of the electrolytic solution in a conventional battery.

Hereinafter, an embodiment of the power storage element according to the present invention will be described with reference to FIGS. 1 to 12. The power storage element includes a secondary battery, a capacitor, and the like. In the present embodiment, a rechargeable secondary battery will be described as an example of the power storage element. The name of each component (each component) of the present embodiment is that of the present embodiment, and may be different from the name of each component (each component) in the background technology.

The power storage element of this embodiment is a non-aqueous electrolyte secondary battery. More specifically, the power storage element is a lithium ion secondary battery that utilizes the electron transfer that occurs with the movement of lithium ions. This type of power storage element supplies electrical energy. The power storage element may be used alone or in combination of two or more. Specifically, the power storage element is used alone when the required output and the required voltage are small. On the other hand, when at least one of the required output and the required voltage is large, the power storage element is used in the power storage device in combination with another power storage element. In the power storage device, the power storage element used in the power storage device supplies electrical energy.

As shown in FIGS. 1 to 4 and 10, the power storage element contains an electrolytic solution, an electrode body 2 having electrodes 23 and 24 including an active material layer 232 and 242, and an electrolytic solution and an electrode body 2 inside. The case 3 to be housed, the external terminal 4 arranged on the outer surface of the wall portion 32 extending in a plane in the case 3, and the electrode body 2 and the external terminal 4 when the internal pressure of the case 3 becomes a predetermined value or more. A current cutoff mechanism 7 that cuts off the connecting conduction path is provided. Further, the power storage element 1 includes a current collector 5 that conducts the electrode body 2 and the external terminal 4, and an insulating member 6 that insulates between the electrode body 2 and the case 3. The power storage element 1 of the present embodiment also includes an insulating member 9 that insulates the case 3 and the external terminal 4. In the power storage element 1 of the present embodiment, the active material layer has a positive electrode active material layer 232 and a negative electrode active material layer 242, and the electrode has a positive electrode 23 and a negative electrode 24.

The electrode body 2 includes a winding core 21, a laminated body 22 in which a positive electrode 23 and a negative electrode 24 are laminated in a state of being insulated from each other, and a laminated body 22 wound around the winding core 21. (See FIGS. 3 and 4). Lithium ions move between the positive electrode 23 and the negative electrode 24 in the electrode body 2, so that the power storage element 1 is charged and discharged.

The winding core 21 is usually formed of an insulating material. The winding core 21 of the present embodiment has a tubular shape, more specifically, a flat tubular shape. The winding core 21 is formed by winding a flexible or thermoplastic sheet. The sheet of the present embodiment is made of a synthetic resin.

The positive electrode 23 has a strip-shaped metal foil 231 and a positive electrode active material layer 232 superimposed on the metal foil 231. The positive electrode active material layer 232 is superposed on the metal leaf 231 in a state where one edge portion (uncovered portion) in the width direction (short direction) of the metal foil 231 is exposed. The metal foil 231 of the present embodiment is, for example, an aluminum foil.

The positive electrode active material layer 232 has a positive electrode active material and a binder.

The positive electrode active material is, for example, a lithium metal oxide. Specifically, the positive electrode active material is, for example, _a composite oxide represented by Li a Me _b O _c (Me represents one or more transition metals) (Li _a Co _y O ₂ , Li _a Ni _{x). O 2, Li a Mn z O} 4, Li a Ni x Co y Mn z O 2 , _{etc.), Li a Me b (XO} c) d (Me represents one or more transition metals, X is for example P , Si, B, a polyanion compounds represented by the representative of the _{V) (Li a Fe b PO} 4, Li a Mn b PO 4, Li a Mn b SiO 4, Li a Co b PO 4 F , etc.). The positive electrode active material of this embodiment is LiNi _1/3 Co _1/3 Mn _1/3 O ₂ .

The binder used for the positive electrode active material layer 232 is, for example, polyvinylidene fluoride (PVdF), a copolymer of ethylene and vinyl alcohol, polymethylmethacrylate, polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyacrylic acid, polymethacryl. Acid, styrene-butadiene rubber (SBR). The binder of this embodiment is polyvinylidene fluoride.

The positive electrode active material layer 232 may further have a conductive auxiliary agent such as Ketjen Black (registered trademark), acetylene black, and graphite. The positive electrode active material layer 232 of the present embodiment has acetylene black as a conductive auxiliary agent.

The negative electrode 24 has a strip-shaped metal foil 241 and a negative electrode active material layer 242 superimposed on the metal foil 241. The negative electrode active material layer 242 is in a state in which the edge portion (uncoated portion) of the metal foil 241 in the width direction (short direction) and the other end (opposite side to the uncoated portion of the metal foil 231 of the positive electrode 23) is exposed. It is overlapped with the metal foil 241. The metal leaf 241 of the present embodiment is, for example, a copper foil. The width direction dimension of the negative electrode active material layer 242 of the present embodiment is larger than the width direction dimension of the positive electrode active material layer 232.

The negative electrode active material layer 242 has a negative electrode active material and a binder.

The negative electrode active material is, for example, a carbon material such as graphite, non-graphitized carbon, and easily graphitized carbon, or a material that undergoes an alloying reaction with lithium ions such as silicon (Si) and tin (Sn). The negative electrode active material of the present embodiment is non-graphitized carbon.

The binder used for the negative electrode active material layer 242 is the same as the binder used for the positive electrode active material layer 232. The binder of this embodiment is polyvinylidene fluoride.

The negative electrode active material layer 242 may further have a conductive auxiliary agent such as Ketjen Black (registered trademark), acetylene black, and graphite. The negative electrode active material layer 242 of the present embodiment does not have a conductive auxiliary agent.

In the electrode body 2 of the present embodiment, the positive electrode 23 and the negative electrode 24 configured as described above are wound in a state of being insulated by the separator 25. That is, in the electrode body 2 of the present embodiment, the laminated body 22 of the positive electrode 23, the negative electrode 24, and the separator 25 is wound.

The separator 25 is an insulating member and is arranged between the positive electrode 23 and the negative electrode 24. As a result, in the electrode body 2 (specifically, the laminated body 22), the positive electrode 23 and the negative electrode 24 are insulated from each other. Further, the separator 25 holds the electrolytic solution in the case 3. As a result, when the power storage element 1 is charged and discharged, lithium ions can move between the positive electrode 23 and the negative electrode 24, which are alternately laminated with the separator 25 in between.

The separator 25 is strip-shaped and is made of, for example, a polyporous membrane such as polyethylene, polypropylene, cellulose, or polyamide. In the separator 25 of the present embodiment _{, an inorganic layer containing inorganic particles such as SiO 2} particles, Al ₂ O ₃ particles, and boehmite (alumina hydrate) is provided on a base material formed of a polyporous film. It is formed by. The base material of the separator 25 of the present embodiment is formed of, for example, polyethylene.

The width direction (short direction) of the separator 25 is larger than the width of the negative electrode active material layer 242. The separator 25 is arranged between the positive electrode 23 and the negative electrode 24 in which the positive electrode active material layer 232 and the negative electrode active material layer 242 are overlapped with each other in a state of being displaced in the width direction so as to overlap in the thickness direction. At this time, the uncoated portion of the positive electrode 23 (the portion where the metal foil 231 is exposed) and the uncoated portion of the negative electrode 24 (the portion where the metal foil 241 is exposed) do not overlap. That is, the uncoated portion of the positive electrode 23 protrudes in the width direction (direction orthogonal to the stacking direction) from the overlapping region of the positive electrode 23 and the negative electrode 24, and the uncoated portion of the negative electrode 24 is the positive electrode 23 and the negative electrode 24. It protrudes from the overlapping region in the width direction (the direction opposite to the protruding direction of the uncoated portion of the positive electrode 23). The electrode body 2 is formed by winding the positive electrode 23, the negative electrode 24, and the separator 25 (that is, the laminated body 22) laminated in such a state. Further, in the electrode body 2 of the present embodiment, the uncoated laminated portion 26 in the electrode body 2 is configured by the portion where only the uncoated portion of the positive electrode 23 or the uncoated portion of the negative electrode 24 is laminated.

The uncoated laminated portion 26 is a portion of the electrode body 2 that is electrically connected to the current collector 5. The uncoated laminated portion 26 of the present embodiment has two hollow portions 27 (see FIGS. 2 and 4) when viewed from the winding central axis direction of the wound positive electrode 23, the negative electrode 24, and the separator 25. It is divided into parts (divided uncoated laminated parts) 261.

The uncoated laminated portion 26 configured as described above is provided at each electrode of the electrode body 2. That is, the uncoated laminated portion 26 in which only the uncoated portion of the positive electrode 23 is laminated constitutes the uncoated laminated portion of the positive electrode in the electrode body 2, and the uncoated laminated portion 26 in which only the uncoated portion of the negative electrode 24 is laminated is formed. It constitutes an uncoated laminated portion of the negative electrode in the electrode body 2.

The case 3 has a case main body 31 having an opening and a lid plate 32 that closes (closes) the opening of the case main body 31. In the case 3 of the present embodiment, the wall portion extending in a plane in which the external terminal 4 is arranged is the lid plate 32. The case 3 houses the electrolytic solution in the internal space 33 (see FIGS. 3 and 10) together with the electrode body 2, the current collector 5, the current cutoff mechanism 7, and the like. Therefore, the case 3 is formed of a metal that is resistant to the electrolytic solution. Case 3 of the present embodiment is formed of, for example, aluminum or an aluminum-based metal material such as an aluminum alloy.

As shown in FIGS. 1 to 3, the case 3 is formed by joining the opening peripheral edge portion 34 of the case main body 31 and the peripheral edge portion of the lid plate 32 in a superposed state. Further, in the case 3, the internal space 33 is defined by the case main body 31 and the lid plate 32. In the case 3 of the present embodiment, the opening peripheral edge portion 34 of the case body 31 and the peripheral edge portion of the lid plate 32 are joined by welding.

The case body 31 includes a plate-shaped closing portion 311 and a cylindrical body portion 312 connected to the peripheral edge of the closing portion 311.

The closing portion 311 is located at the lower end of the case body 31 when the case body 31 is arranged with the opening facing upward (that is, becomes the bottom wall of the case body 31 when the opening faces upward). ) The part. The closed portion 311 has a rectangular shape when viewed from the normal direction of the closed portion 311.

In the following, the long side direction of the closed portion 311 is the X-axis direction, the short side direction of the closed portion 311 is the Y-axis direction, and the normal direction of the closed portion 311 is the Z-axis direction. Along with this, the Cartesian coordinate axes corresponding to the X-axis direction, the Y-axis direction, and the Z-axis direction are supplementarily illustrated in each drawing.

The body portion 312 has a square tube shape, more specifically, a flat square tube shape. The body portion 312 has a pair of long wall portions 313 extending from the long side at the peripheral edge of the closed portion 311 and a pair of short wall portions 314 extending from the short side at the peripheral edge of the closed portion 311. That is, the pair of long wall portions 313 face each other with an interval in the Y-axis direction (specifically, the interval corresponding to the short side at the peripheral edge of the closed portion 311), and the pair of short wall portions 314 are spaced in the X-axis direction. (Specifically, they face each other with an interval corresponding to the long side at the peripheral edge of the closed portion 311). The short wall portion 314 connects the corresponding ends of the pair of long wall portions 313 (specifically, the ends facing each other in the Y-axis direction) to form a square tubular body portion 312.

As described above, the case body 31 has a square tube shape (that is, a bottomed square tube shape) in which one end in the opening direction (Z-axis direction) is closed.

The lid plate 32 is a plate-shaped member that closes the opening of the case body 31. Specifically, the lid plate 32 has a contour shape corresponding to the opening peripheral edge portion 34 of the case main body 31 when viewed from the Z-axis direction. That is, the lid plate 32 is a rectangular plate material that is long in the X-axis direction when viewed from the Z-axis direction. The lid plate 32 comes into contact with the case body 31 so as to close the opening of the case body 31. More specifically, the peripheral edge portion of the lid plate 32 is overlapped with the opening peripheral edge portion 34 of the case body 31 so that the lid plate 32 closes the opening. The boundary between the lid plate 32 and the case body 31 is welded in a state where the opening peripheral edge portion 34 and the lid plate 32 are overlapped with each other. As a result, the case 3 is configured.

The lid plate 32 has a gas discharge valve 321 capable of discharging the gas in the case 3 to the outside. The gas discharge valve 321 discharges gas from the inside of the case 3 to the outside when the internal pressure of the case 3 rises to a predetermined pressure (a predetermined value at which the case 3 does not burst or the like: the first threshold value). .. The gas discharge valve 321 of the present embodiment is provided at the center of the lid plate 32 in the X-axis direction.

Specifically, the gas discharge valve 321 has a thin-walled portion in which a breaking groove is formed. When the internal pressure (gas pressure) of the case 3 exceeds the first threshold value, the thin-walled portion of the gas discharge valve 321 tears from the breaking groove, so that the internal (internal space 33) and the external (external space) of the case 3 are separated. ) And communicate. As a result, the gas discharge valve 321 discharges the gas inside the case 3 to the outside. In this way, the gas discharge valve 321 lowers the increased internal pressure of the case 3.

The lid plate 32 is provided with a pair of through holes 322 for communicating the inside and the outside of the case 3. Each of the pair of through holes 322 is used to conduct the electrode body 2 housed inside the case 3 and the external terminal 4 which is at least partially arranged outside the case 3. Specifically, each of the pair of through holes 322 penetrates the lid plate 32 in the Z-axis direction (thickness direction). Each of the pair of through holes 322 is provided at both ends of the lid plate 32 in the X-axis direction. That is, the pair of through holes 322 are provided in the lid plate 32 at intervals in the X-axis direction. The shaft portion 42 of the external terminal 4 is inserted into the through hole 322 (see FIGS. 2 and 3).

The external terminal 4 is a portion electrically connected to an external terminal of another power storage element, an external device, or the like. The power storage element 1 of the present embodiment includes a pair of external terminals 4. One external terminal 4 is a positive electrode external terminal 4A conducting with the positive electrode 23 of the electrode body 2, and the other external terminal 4 is a negative electrode external terminal 4B conducting with the negative electrode 24 of the electrode body 2. The external terminal 4 is formed of a metal material having conductivity and high weldability. For example, the positive electrode external terminal 4A is formed of an aluminum-based metal material such as aluminum or an aluminum alloy, and the negative electrode external terminal 4B is formed of a copper-based metal material such as copper or a copper alloy.

Specifically, as shown in FIGS. 2, 3, 5 and 9, the external terminal 4 has a head 41 arranged on the outer surface of the lid plate 32 and a shaft portion 42 extending from the head 41. Have.

The head 41 is a plate-shaped portion extending along the lid plate 32. The head 41 of the present embodiment has a rectangular plate shape.

The shaft portion 42 extends from the surface of the head 41 on the lid plate 32 side toward the inside of the case 3 through the through hole 322 of the lid plate 32. Before being assembled to the lid plate 32, the shaft portion 42 is a tubular portion that defines a non-penetrating hole 421 extending from the tip end of the shaft portion 42 toward the base portion (head 41 side) (see FIG. 9). ), After being assembled to the lid plate 32, the portion on the tip side is expanded outward in the radial direction of the shaft portion 42 by caulking to form a collar shape (large diameter portion 423) (FIGS. 5 and 6). reference). That is, the shaft portion 42 after assembly includes a large diameter portion 423 at the tip portion. In the power storage element 1 of the present embodiment, the head 41 and the large diameter portion 423 have the insulating member 9 (in the example of the present embodiment, the internal insulating member 91 and the external insulating member 92) together with the lid plate 32 in the Z-axis direction. By sandwiching the members 91 and 92, the members 91 and 92 are fixed to the lid plate 32. In the positive electrode external terminal 4A, the head 41 and the large diameter portion 423 are in the Z-axis direction together with the insulating member 9 (internal insulating member 91 and external insulating member 92) and a part of the current cutoff mechanism 7 together with the lid plate 32. The current cutoff mechanism 7 is also fixed to the lid plate 32 so as to be sandwiched between the two (see FIGS. 6 and 7). The positive electrode external terminal 4A also has a connection hole 422 that communicates the non-penetrating hole 421 with the outside. The specific arrangement position of the connection hole 422 is not limited, and it may be an arrangement in which the non-penetrating hole 421 and the outside communicate with each other in a state where the bus bar or the like is connected to the external terminal 4 by welding or the like.

The insulating member 9 includes a plurality of insulating members. In the example of the present embodiment, the insulating member 9 includes an internal insulating member 91 arranged inside the case 3 and an external insulating member 92 arranged outside the case 3.

The internal insulating member 91 has an insulating property and insulates the lid plate 32 from the current collector 5 or the current cutoff mechanism 7. The internal insulating member 91 is arranged between the lid plate 32 and the current blocking mechanism 7 inside the case 3 on the positive electrode external terminal 4A side, and with the lid plate 32 inside the case 3 on the negative electrode external terminal 4B side. It is arranged between the current collector 5 and the current collector 5. The internal insulating member 91 of the present embodiment is formed of an insulating resin.

Specifically, the internal insulating member 91 is a plate-shaped member. The internal insulating member 91 of the present embodiment has a rectangular plate-shaped base portion 911 that extends along the inner surface of the lid plate 32 and is long in the X-axis direction, and the inside of the case 3 from the peripheral edge of the base portion 911 (the side opposite to the lid plate 32). It has a peripheral wall portion 912 that protrudes toward and extends along the peripheral edge. In the internal insulating member 91, the base portion 911 and the peripheral wall portion 912 form a recess 913 into which a part of the current collector 5 or a part of the current cutoff mechanism 7 is fitted. The base portion 911 has a hole 914 through which the shaft portion 42 of the external terminal 4 is inserted at a position overlapping the through hole 322 of the lid plate 32 in the Z-axis direction.

The external insulating member 92 has an insulating property and insulates the lid plate 32 and the external terminal 4. The external insulating member 92 is arranged between the lid plate 32 and the external terminal 4. Further, the external insulating member 92 seals (seals) between the lid plate 32 and the external terminal 4. That is, the external insulating member 92 has an insulating property and a sealing property. The external insulating member 92 of the present embodiment is formed of an insulating resin.

Specifically, the external insulating member 92 projects from the peripheral edge of the base portion 921 extending along the outer surface of the lid plate 32 and the peripheral edge of the base portion 921 toward the outside of the case 3 (the side opposite to the lid plate 32) and along the peripheral edge. It has a peripheral wall portion 922 extending so as to extend, and an annular convex portion 923 connected to the side opposite to the peripheral wall portion 922 in the base portion 921. In the external insulating member 92, the base portion 921 and the peripheral wall portion 922 form a recess 924 into which the head 41 of the external terminal 4 is fitted.

The annular convex portion 923 is a cylindrical portion extending from the base portion 921 into the through hole 322 of the lid plate 32. The inner peripheral surface of the annular convex portion 923 and the inner peripheral surface defining the hole 914 of the base portion 921 are connected to each other. The annular convex portion 923 is fitted without a gap between the shaft portion 42 inserted into the through hole 322 of the lid plate 32 and the inner peripheral surface defining the through hole 322 of the lid plate 32. As a result, the annular convex portion 923 insulates between the shaft portion 42 and the inner peripheral surface defining the through hole 322 of the lid plate 32. Further, the annular convex portion 923 seals between the shaft portion 42 and the inner peripheral surface defining the through hole 322 of the lid plate 32.

As shown in FIGS. 6 to 8, the current cutoff mechanism 7 has a diaphragm (pressure receiving portion) 71 arranged inside the case 3, and when the diaphragm 71 receives a pressure equal to or higher than a predetermined value, the external terminal 4 The conduction path connecting the electrode body 2 and the electrode body 2 is cut off. The current cutoff mechanism 7 of the present embodiment cuts off the conduction path connecting the positive electrode external terminal 4A and the positive electrode 23 of the electrode body 2.

Specifically, the current cutoff mechanism 7 is arranged between the diaphragm 71, the cutoff mechanism conductive portion 72 for conducting the diaphragm 71 and the positive electrode external terminal 4A, the cutoff mechanism conductive portion 72, and the current collector 5 to cut off the current. It has a blocking mechanism insulating portion 73 that insulates between the mechanism conductive portion 72 and the current collector 5.

The blocking mechanism conductive portion 72 is formed of a conductive member such as metal. The blocking mechanism conductive portion 72 includes a plate-shaped first base portion 721 extending along the lid plate 32, a first peripheral wall portion 722 rising from the peripheral edge of the first base portion 721, and a first base portion in the first peripheral wall portion 722. It has a first flange portion 723 extending substantially parallel to the first base portion 721 from an end opposite to the 721. The first base portion 721 of the present embodiment has a rectangular plate shape, and has a through hole 724 at a position overlapping the through hole 322 of the lid plate 32. The peripheral edge of the through hole 724 of the first base portion 721 is Z by the head 41 of the positive electrode external terminal 4A and the large diameter portion 423 together with the lid plate 32 and the insulating member 9 (internal insulating member 91 and external insulating member 92). By being sandwiched in the axial direction, the cutoff mechanism conductive portion 72 and the positive electrode external terminal 4A become conductive.

The blocking mechanism insulating portion 73 is composed of a member having an insulating property such as resin. The blocking mechanism insulating portion 73 includes a plate-shaped second base portion 731 that extends substantially parallel to the first base portion 721, a second peripheral wall portion 732 that rises from the peripheral edge of the second base portion 731, and a second base portion in the second peripheral wall portion 732. It has a second flange portion 733 extending substantially parallel to the second base portion 731 from an end opposite to the 731. The second base portion 731 has a rectangular plate shape corresponding to the first base portion 721. The second base portion 731 has a first through hole 7311 in the center and one or more (plural) second through holes 7312 around the first through hole 7311. A part of the current collector 5 is inserted into the first through hole 7311 of the second base portion 731. Further, the second flange portion 733 overlaps with the first flange portion 723 in a state where the peripheral edge portion of the diaphragm 71 is sandwiched between the second flange portion 733 and the first flange portion 723. At this time, the first flange portion 723 and the peripheral edge portion of the diaphragm 71 are in close contact (close) with each other in an airtight state, and the second flange portion 733 and the peripheral edge portion of the diaphragm 71 are in close contact (close) with each other in an airtight state. ing.

The diaphragm 71 is a metal thin plate-shaped member, and its peripheral edge portion is sandwiched between the first flange portion 723 and the second flange portion 733. As a result, the space surrounded by the cutoff mechanism conductive portion 72 and the diaphragm 71 (external side space 711) and the space surrounded by the cutoff mechanism insulating portion 73 and the diaphragm 71 (internal side space 712) become the diaphragm 71. Separated by. At this time, the external space 711 communicates with the outside (outside the power storage element 1) through the non-penetrating hole 421 and the connection hole 422 of the positive electrode external terminal 4A, and the internal space 712 is the first through hole 7311 and It communicates with the internal space 33 of the case 3 through the second through hole 7312.

The thin plate-shaped diaphragm 71 bulges toward the cutoff mechanism insulating portion 73, and the most bulging central portion 713 is the current collector 5 inserted into the first through hole 7311 of the cutoff mechanism insulating portion 73. (See FIG. 6). As a result, the diaphragm 71 conducts the current collector 5 and the cutoff mechanism conductive portion 72. That is, a conduction path is formed from the current collector 5 to the positive electrode external terminal 4A via the diaphragm 71 and the cutoff mechanism conduction portion 72.

The diaphragm 71 receives the internal pressure of the case 3 through the first through hole 7311 and the second through hole 7312. Then, when the internal pressure of the case 3 becomes equal to or higher than the second threshold value (a value lower than the first threshold value which is the operating pressure of the gas discharge valve 321), the diaphragm 71 has a central portion as shown in FIG. The 713 is separated from the current collector 5 and bulges toward the interruption mechanism conductive portion 72. As a result, the conduction path connecting the current collector 5 and the positive electrode external terminal 4A (that is, the conduction path connecting the positive electrode external terminal 4A and the positive electrode 23 of the electrode body 2) is cut off.

The current collector 5 is arranged in the case 3 and is directly or indirectly connected to the electrode body 2 so as to be conductive. As shown in FIGS. 2 and 3, the current collector 5 of the present embodiment is electrically conductively connected to the electrode body 2 via the clip member 50. That is, the power storage element 1 includes a clip member 50 that electrically connects the electrode body 2 and the current collector 5. The clip member 50 sandwiches the positive electrode 23 or the negative electrode 24 laminated in the uncoated laminated portion 26 (specifically, the divided uncoated laminated portion 261) of the electrode body 2 so as to bundle them. As a result, the clip member 50 makes the positive electrodes 23 and the negative electrodes 24 laminated in the uncoated laminated portion 26 conductive to each other. The clip member 50 of the present embodiment is formed by bending a plate-shaped metal material so that a cross section along an XY plane (a plane including the X-axis and the Y-axis) is U-shaped. .. In the present embodiment, the two clip members 50 are arranged on the uncoated laminated portion 26 of the positive electrode 23 of the electrode body 2, and the two clip members 50 are arranged on the uncoated laminated portion 26 of the negative electrode 24.

The current collector 5 is composed of a conductive member and is arranged along the inner surface of the case 3. The current collector 5 of the present embodiment conducts the external terminal 4 and the clip member 50. Specifically, as shown in FIGS. 5 to 8, the current collector 5 is connected to the external terminal 4 directly or indirectly via the current cutoff mechanism 7 so as to be conductively connected to the first connecting portion 51 and the electrodes. It has a second connecting portion 52 that is electrically connected to the body 2 and a bent portion 53 that connects the first connecting portion 51 and the second connecting portion 52. In the current collector 5, the bent portion 53 is arranged near the boundary between the lid plate 32 and the short wall portion 314 in the case 3, and the first connecting portion 51 extends from the bent portion 53 substantially parallel to the lid plate 32. The second connecting portion 52 extends from the bent portion 53 substantially parallel to the short wall portion 314. That is, the current collector 5 is formed in an L shape (see FIGS. 2 and 3).

The first connecting portion 51 is a plate-shaped portion extending from the bent portion 53 substantially parallel to the inner surface of the case 3 (cover plate 32) in a state of being insulated from the case 3 (specifically, the lid plate 32). A through hole 54 is formed at the tip of the first connecting portion 51 (the end opposite to the bent portion 53). The through hole 54 is provided at a position where it overlaps with the through hole 322 of the lid plate 32 in the Z-axis direction.

In the first connection portion 51A on the positive electrode side (the first connection portion 51 in the current collector 5 connected to the positive electrode 23 of the electrode body 2), the periphery of the through hole 54 projects toward the lid plate 32. The protruding portion (protruding portion) 511 fits into the first through hole 7311 of the blocking mechanism insulating portion 73. That is, the tip of the first connection portion 51A on the positive side has a through hole 54 penetrating in the Z-axis direction at the center, and is fitted (inserted) into the first through hole 7311 of the second base portion 731. It has a cylindrical protrusion 511. Then, the internal space 712 communicates with the internal space 33 of the case 3 through the through hole 54 of the first connecting portion 51. With the protrusion 511 fitted into the first through hole 7311, the tip surface 512 of the protrusion 511 is flush with the inner surface (the surface facing the internal space 712) 7315 of the second base portion 731, or the inner surface 7315. It slightly protrudes toward the inner space 712. The tip surface 512 is in contact with the diaphragm 71 (specifically, the central portion 713) when the internal pressure of the case 3 is less than the second threshold value (see FIG. 6).

Further, the first connection portion 51A on the positive electrode side has a through hole 55 at a position overlapping with the second through hole 7312 of the cutoff mechanism insulating portion 73. The internal side space 712 and the internal space 33 of the case are also communicated with each other by the hole in which the second through hole 7322 and the through hole 55 are connected in the Z-axis direction. In the power storage element 1 of the present embodiment, since a plurality of second through holes 7322 are provided in the cutoff mechanism insulating portion 73, the number of the first connection portions 51A on the positive electrode side is also a plurality (that is, the number of the second through holes 7322). The number of through holes 55 corresponding to the above) is provided.

On the other hand, only the through hole 54 is provided in the first connection portion 51B on the negative electrode side (the first connection portion 51 in the current collector 5 connected to the negative electrode 24 of the electrode body 2) (see FIG. 2). Then, the peripheral edge of the through hole 54 is sandwiched between the head 41 of the negative electrode external terminal 4B and the large diameter portion 423 together with the lid plate 32 and the insulating member 9, so that the first connection portion 51B on the negative electrode side is the external terminal. Conducts with 4 (see FIG. 5).

The second connecting portion 52 is conductively connected to the electrode body 2 (in this embodiment, the uncoated laminated portion 26 of the electrode body 2 via the clip member 50). Specifically, the second connecting portion 52 extends from the bent portion 53 along the inner surface of the case 3 (short wall portion 314) in a state of being insulated from the case 3 (specifically, the short wall portion 314). The second connecting portion 52 extends from the vicinity of the short wall portion 314 toward the uncoated laminated portion 26 and extends in the same direction as the second connecting portion 52 (two in the example of the present embodiment). Has 56. The joining piece 56 is joined to the clip member 50. The bonding piece 56 of this embodiment is bonded to the clip member 50 by, for example, ultrasonic welding.

In the current collector 5 configured as described above, the positive electrode side current collector 5 arranged in the vicinity of the uncoated laminated portion 26 of the positive electrode 23 in the electrode body 2 is formed of, for example, aluminum or an aluminum alloy. The current collector 5 on the negative electrode side arranged in the vicinity of the uncoated laminated portion 26 of the negative electrode body 2 in the electrode body 2 is formed of, for example, copper or a copper alloy.

As shown in FIGS. 2 and 3, the insulating member 6 is arranged between the case 3 (specifically, the case body 31) and the electrode body 2. The insulating member 6 of the present embodiment is formed in a bag shape by bending a sheet-shaped member having an insulating property cut into a predetermined shape.

The electrolytic solution is a non-aqueous electrolyte solution. The electrolytic solution is obtained by dissolving an electrolyte salt in an organic solvent. The organic solvent is, for example, cyclic carbonates such as propylene carbonate and ethylene carbonate, and chain carbonates such as dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate. Electrolyte salts are LiClO ₄ , LiBF _{4 , LiPF 6} , and the like. _{The electrolytic solution of the present embodiment contains 1 mol / L LiPF 6} in a mixed solvent prepared by adjusting propylene carbonate, dimethyl carbonate, and ethyl methyl carbonate in a ratio of propylene carbonate: dimethyl carbonate: ethyl methyl carbonate = 3: 2: 5. Is dissolved.

In the power storage element 1 of the present embodiment, an amount of an electrolytic solution larger than the amount that can be held by the electrode body 2 (specifically, the separator 25) is injected into the case 3. That is, a predetermined amount of the electrolytic solution is accumulated inside the case 3 without being held by the electrode body 2. Hereinafter, the accumulated electrolytic solution may be referred to as a surplus electrolytic solution.

Specifically, the first posture in which the outer surface of the lid plate 32 faces upward, that is, the posture in which the outer surface of the lid plate 32 faces the horizontal direction (see FIG. 10), and the second posture in which the outer surface of the lid plate 32 faces the horizontal direction. In the posture, that is, in the posture in which the outer surface of the lid plate 32 is along the vertical direction (for example, see FIG. 11 as an example), the excess electrolytic solution accumulated inside the case 3 is the active material layer 232, 242 of the electrode body 2. (Preferably, there is a liquid level of excess electrolytic solution in contact with the positive electrode active material layer 232) and below the diaphragm 71 (specifically, the first through hole 7311 and the second through hole 7312) of the current cutoff mechanism 7. More specifically, the first posture, the second posture, and the third posture in which the outer surface of the lid plate 32 faces in each direction from the direction in which the first posture faces to the direction in which the lid plate 32 faces in the second posture (for example, FIG. 12 as an example). In any of the postures (see), the excess electrolytic solution accumulated inside the case 3 is in contact with the active material layer 232 and 242 (preferably the positive electrode active material layer 232) of the electrode body 2, and the current cutoff mechanism. There is a liquid level of excess electrolytic solution below the diaphragm 71 (first through hole 7311 and second through hole 7312) of No. 7.

In the power storage element 1 of the present embodiment, the overcharge inhibitor that generates gas when in contact with the electrode body 2 in the overcharged state (specifically, the active material layer 232, 242, particularly the positive electrode active material layer 232) is used as the electrolytic solution. Has been added. The overcharge inhibitor is, for example, cyclohexylbenzene, biphenyl, 1,3,5-trimethylbenzene.

According to the above-mentioned power storage element 1, if the power storage element 1 is arranged so that the case 3 (power storage element 1) is in the first posture, the second posture, and the third posture, the active material layer 232 and 242 will be formed. The diaphragm 71 (specifically, the first through hole 7311 and the second through hole 7312) is located above the excess electrolyte accumulated inside the case 3 even if it is in contact with the excess electrolyte accumulated inside the case 3. do. Therefore, at the time of overcharging, that is, when the internal pressure of the case 3 reaches the second threshold value (set value), the current cutoff mechanism 7 operates accurately, thereby accurately overcharging the power storage element 1. Can be prevented.

In the power storage element 1 of the present embodiment, an overcharge inhibitor is added to the electrolytic solution. Therefore, more gas is generated inside the case 3 at the time of overcharging, so that the internal pressure of the case 3 rises sufficiently at the time of overcharging, so that the current cutoff mechanism 7 operates more accurately. As a result, overcharging of the power storage element 1 can be prevented more accurately.

In the power storage element 1, when the positive electrode active material layer 232 is in contact with the electrolytic solution and is overcharged, the case where the negative electrode active material layer 242 is in contact with the electrolytic solution is overcharged. , A large amount of gas is generated. Therefore, in each of the first to third postures, if an amount of electrolyte that allows the positive electrode active material layer 232 to come into contact with the excess electrolyte is injected into the case 3, the first to third postures are used. More gas is generated inside the case 3 during overcharging than in the case where the negative electrode active material layer 242 is in contact with the excess electrolytic solution in each posture. As a result, the current cutoff mechanism 7 operates more accurately at the time of overcharging, and as a result, overcharging of the power storage element 1 can be prevented more accurately. In the second and third postures, when the positive electrode active material layer 232 comes into contact with the excess electrolyte, the positive electrode external terminal 4A is lower than the negative electrode external terminal 4B in the various second and third postures. It means that the positive electrode active material layer 232 comes into contact with the excess electrolytic solution when the posture is such that it is located at.

Further, in the power storage element 1 of the present embodiment, the current cutoff mechanism 7 cuts off the conduction path connecting the positive electrode external terminal 4A and the positive electrode 23 of the electrode body 2. By arranging the current cutoff mechanism 7 at a position close to the positive electrode 23 of the electrode body 2 (the conduction path connecting the positive electrode external terminal 4A and the positive electrode 23 of the electrode body 2) in this way, the electrode body 2 is overcharged. Since gas is likely to be generated on the positive electrode side of the above, the responsiveness to overcharging (specifically, the increase in internal pressure due to the gas generated during overcharging) is improved. As a result, overcharging of the power storage element 1 can be prevented more accurately.

The power storage element of the present invention is not limited to the above embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and a part of the configuration of one embodiment can be replaced with the configuration of another embodiment. In addition, some of the configurations of certain embodiments can be deleted.

The specific configuration of the current cutoff mechanism 7 is not limited. For example, the current cutoff mechanism 7 of the above embodiment has a configuration in which a diaphragm 71 is used as a pressure receiving portion and the diaphragm 71 is a part of a conduction path, but the present invention is not limited to this configuration. The current cutoff mechanism 7 may be configured not to use the diaphragm 71. That is, if the current cutoff mechanism 7 is configured to cut off the conduction path connecting the external terminal 4 and the electrode body 2 when the pressure receiving portion receiving the internal pressure of the case 3 receives a pressure equal to or higher than the second threshold value. good.

In the power storage element 1 of the above embodiment, the current cutoff mechanism 7 cuts off the conduction path connecting the positive electrode external terminal 4A and the positive electrode 23 of the electrode body 2, but the present invention is not limited to this configuration. The current cutoff mechanism 7 may be configured to cut off the conduction path connecting the negative electrode external terminal 4B and the negative electrode 24 of the electrode body 2, and the conduction path connecting the positive electrode external terminal 4A and the positive electrode 23 of the electrode body 2 and the negative electrode external terminal. The configuration may be such that each conduction path of the conduction path connecting the 4B and the negative electrode 24 of the electrode body 2 is cut off. That is, the current cutoff mechanism 7 may be arranged in the conduction path connecting the negative electrode external terminal 4B and the negative electrode 24 of the electrode body 2, and the conduction path connecting the positive electrode external terminal 4A and the positive electrode 23 of the electrode body 2 and the negative electrode. It may be arranged in each conduction path of the conduction path connecting the external terminal 4B and the negative electrode 24 of the electrode body 2.

Further, in the power storage element 1 of the above embodiment, the wall portion on which the external terminal 4 of the case 3 is arranged is the lid plate 32, but the present invention is not limited to this configuration. For example, the external terminal 4 may be arranged on the long wall portion 313, the short wall portion 314, or the closed portion 311. That is, the external terminal 4 may be arranged in a portion of the case 3 that spreads out in a plane.

Further, in the power storage element 1 of the above embodiment, an overcharge inhibitor is added to the electrolytic solution, but the configuration is not limited to this. The overcharge inhibitor may not be added to the electrolytic solution.

The electrode body 2 of the above embodiment is a so-called winding type electrode body in which the positive electrode 23 and the negative electrode 24 are wound in a state of being laminated via the separator 25, but the positive electrode 23 and the negative electrode 24 are leaf-shaped. May be a so-called laminated electrode body in which the electrodes are laminated via the separator 25.

Further, in the above embodiment, the case where the power storage element is used as a chargeable / dischargeable non-aqueous electrolyte secondary battery (for example, a lithium ion secondary battery) has been described, but the type and size (capacity) of the power storage element are arbitrary. Is. Further, in the above embodiment, the lithium ion secondary battery has been described as an example of the power storage element, but the present invention is not limited to this. For example, the present invention can be applied to various secondary batteries and other storage elements of capacitors such as electric double layer capacitors.

The power storage element (for example, a battery) 1 may be used in a power storage device (battery module when the power storage element is a battery) 11 as shown in FIG. The power storage device 11 includes at least two power storage elements 1 and a bus bar member 12 that electrically connects two (different) power storage elements 1 to each other. In this case, the technique of the present invention may be applied to at least one power storage element 1.

1 ... power storage element, 2 ... electrode body, 21 ... winding core, 22 ... laminate, 23 ... positive electrode (electrode), 231 ... metal foil, 232 ... positive electrode active material layer (active material layer), 24 ... negative electrode (electrode) , 241 ... Metal foil, 242 ... Negative electrode active material layer (active material layer), 25 ... Separator, 26 ... Uncoated laminated portion, 261 ... Divided uncoated laminated portion, 27 ... Hollow portion, 3 ... Case, 31 ... Case body, 311 ... Closure part, 312 ... Body part, 313 ... Long wall part, 314 ... Short wall part, 32 ... Lid plate (wall part), 321 ... Gas discharge valve, 322 ... Through hole, 33 ... Internal space, 34 ... Opening peripheral edge, 4 ... External terminal, 4A ... Positive electrode external terminal, 4B ... Negative electrode external terminal, 41 ... Head, 42 ... Shaft, 421 ... Tip hole, 422 ... Connection hole, 423 ... Large diameter part, 5 ... Collector, 50 ... Clip member, 51 ... First connection part, 51A ... Positive electrode side first connection part, 51B ... Negative electrode side first connection part, 511 ... Projection part, 512 ... Tip surface, 52 ... Second Connection part, 53 ... Bending part, 54 ... Through hole, 55 ... Through hole, 56 ... Joint piece, 6 ... Insulating member, 7 ... Current cutoff mechanism, 71 ... Diaphragm (pressure receiving part), 711 ... External space, 712 ... Internal side space, 713 ... Central part, 72 ... Breaking mechanism conductive part, 721 ... First base part, 722 ... First peripheral wall part, 723 ... First flange part, 724 ... Through hole, 73 ... Breaking mechanism insulating part, 731 ... Second base, 7311 ... First through hole, 7312 ... Second through hole, 7315 ... Inner surface, 732 ... Second peripheral wall, 733 ... Second flange, 9 ... Insulating member, 91 ... Internal insulating member, 911 ... Base, 912 ... peripheral wall, 913 ... concave, 914 ... hole, 92 ... external insulating member, 921 ... base, 922 ... peripheral wall, 923 ... annular convex, 924 ... concave, 11 ... power storage device, 12 ... bus bar member

Claims (5)

With electrolyte
An electrode body having an electrode containing an active material layer and
A case for accommodating the electrolytic solution and the electrode body inside, and
In the case, the external terminals arranged on the outer surface of the wall portion that spreads out in a plane,
A current collector that conducts the electrode body and the external terminal,
A pressure receiving portion that is arranged inside the case and is in contact with the current collector without being welded, a breaking mechanism conducting portion that conducts the pressure receiving portion and the external terminal, and the breaking mechanism conductive portion and the current collector. The external terminal has a blocking mechanism insulating portion which is arranged between and insulates between the breaking mechanism conductive portion and the current collector, and when the pressure receiving portion receives a pressure equal to or higher than a predetermined value. A current blocking mechanism that cuts off the conduction path connecting the electrode body and the electrode body is provided.
The pressure receiving portion includes a space surrounded by the breaking mechanism conductive portion and the breaking mechanism insulating portion, an external space which is a space surrounded by the pressure receiving portion and the breaking mechanism conductive portion, and the pressure receiving portion. A space surrounded by the blocking mechanism insulating portion, separated from an internal space which is a space communicating with the internal space of the case.
The blocking mechanism insulating portion has a first through hole and a plurality of second through holes arranged around the first through hole.
The current collector has a first connection portion that is arranged so as to overlap the insulation portion of the cutoff mechanism and is indirectly conductively connected to the external terminal via the current cutoff mechanism.
The first connection portion includes a third through hole arranged at a position overlapping the first through hole of the cutoff mechanism insulating portion and a position surrounding the third through hole, and is a second portion of the cutoff mechanism insulating portion. It has a plurality of fourth through holes arranged at positions overlapping with the through holes, and has.
The internal space communicates with the internal space of the case through the first through hole and the third through hole, and the second through hole and the plurality of fourth through holes.
The current blocking mechanism cuts off the conduction path by separating the pressure receiving portion from the state of being in contact with the first connecting portion through the first through hole.
In the first posture in which the outer surface of the wall portion faces upward and the second posture in which the outer surface of the wall portion faces in the horizontal direction, the electrolytic solution accumulated inside the case comes into contact with the active material layer and the pressure receiving portion. Is located above the accumulated electrolyte.
Power storage element. The power storage element according to claim 1, further comprising an overcharge inhibitor that generates gas by coming into contact with the active material layer of the electrode body in an overcharged state and is added to the electrolytic solution. The active material layer has a positive electrode active material layer and a negative electrode active material layer.
The electrode body has a positive electrode including the positive electrode active material layer and a negative electrode including the negative electrode active material layer.
The pair of external terminals has a positive electrode external terminal conducting with the positive electrode and a negative electrode external terminal conducting with the negative electrode.
The power storage element according to claim 1 or 2, wherein the electrolytic solution accumulated inside the case is in contact with the positive electrode active material layer when the case is in the first posture and the second posture. The power storage element according to claim 3, wherein the current cutoff mechanism cuts off a conduction path connecting the positive electrode external terminal and the positive electrode of the electrode body. With electrolyte
An electrode body having an electrode containing an active material layer and
A case for accommodating the electrolytic solution and the electrode body inside, and
In the case, the external terminals arranged on the outer surface of the wall portion that spreads out in a plane,
A current collector that conducts the electrode body and the external terminal,
A pressure receiving portion that is arranged inside the case and is in contact with the current collector without being welded, a breaking mechanism conducting portion that conducts the pressure receiving portion and the external terminal, and the breaking mechanism conductive portion and the current collector. The external terminal has a blocking mechanism insulating portion which is arranged between and insulates between the breaking mechanism conductive portion and the current collector, and when the pressure receiving portion receives a pressure equal to or higher than a predetermined value. A current blocking mechanism that cuts off the conduction path connecting the electrode body and the electrode body is provided.
The pressure receiving portion includes a space surrounded by the breaking mechanism conductive portion and the breaking mechanism insulating portion, an external space which is a space surrounded by the pressure receiving portion and the breaking mechanism conductive portion, and the pressure receiving portion. A space surrounded by the blocking mechanism insulating portion, separated from an internal space which is a space communicating with the internal space of the case.
The blocking mechanism insulating portion has a first through hole and a plurality of second through holes arranged around the first through hole 11.
The current collector has a first connection portion that is arranged so as to overlap the insulation portion of the cutoff mechanism and is indirectly conductively connected to the external terminal via the current cutoff mechanism.
The first connection portion includes a third through hole arranged at a position overlapping the first through hole of the cutoff mechanism insulating portion and a position surrounding the third through hole, and is a second portion of the cutoff mechanism insulating portion. It has a plurality of fourth through holes arranged at positions overlapping with the through holes, and has.
The internal space communicates with the internal space of the case through the first through hole and the third through hole, and the second through hole and the plurality of fourth through holes.
The current blocking mechanism cuts off the conduction path by separating the pressure receiving portion from the state of being in contact with the first connecting portion through the first through hole.
The first posture in which the outer surface of the wall portion faces upward, the second posture in which the outer surface of the wall portion faces in the horizontal direction, and the direction in which the outer surface of the wall portion faces in the first posture to the second posture. In any of the third postures facing each direction up to, the electrolytic solution accumulated inside the case is in contact with the active material layer, and the pressure receiving portion is above the accumulated electrolytic solution. Located, a power storage element.

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