JP2014022285A - Secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that electric energy remains stored in a secondary battery, when a current interruption mechanism disposed in the secondary battery is operated.SOLUTION: The secondary battery has a power generation element including a reaction region where chemical reaction corresponding to charge/discharge takes place, a conductive battery case housing the power generation element, and a current interruption mechanism housed in the battery case and interrupting a current path connected electrically with the power generation element. The battery case has a fragile part formed in a shape for reducing strength thereof, and an outer surface of the battery case corresponding to the fragile part is covered with an insulator having lower rigidity than that of the battery case. The fragile part is a current path in the battery case excepting the reaction region, and provided at a position adjoining a current path located closer to the reaction region side than the current interruption mechanism.

Description

  The present invention is a secondary battery provided with a current interrupting mechanism that interrupts a current path inside the secondary battery.

  In Patent Document 1, a current interruption mechanism is provided inside the secondary battery. Here, when the internal pressure of the secondary battery increases as the secondary battery is overcharged, the current path is interrupted by the deformation of the metal plate included in the current interrupt mechanism. Since the current interruption mechanism is connected to the electrode terminal (positive electrode terminal or negative electrode terminal), when the current interruption mechanism is activated, the secondary battery cannot be charged / discharged via the electrode terminal.

JP 2010-157451 A

  After the current path is interrupted by the current interrupt mechanism, the electrical energy stored in the secondary battery cannot be taken out from the electrode terminal. That is, the secondary battery cannot be discharged through the electrode terminal. As described above, since the current interruption mechanism is activated by overcharging the secondary battery, a lot of electrical energy remains stored in the secondary battery.

  The secondary battery according to the present invention includes a power generation element, a battery case that houses the power generation element and has conductivity, and a current interruption mechanism that is housed in the battery case. The power generation element includes a reaction region in which a chemical reaction corresponding to charge / discharge is performed, and a reaction region and a current path electrically connected to the reaction region are provided inside the battery case. Here, the current interrupting mechanism interrupts a current path electrically connected to the power generation element.

  The battery case has a fragile portion formed in a shape that reduces the strength of the battery case, and the outer surface of the battery case corresponding to the fragile portion is covered with an insulator having a rigidity lower than that of the battery case. The weak part is a current path in the battery case excluding the reaction area, and is provided at a position adjacent to the current path located on the reaction area side with respect to the current interruption mechanism. Here, for example, the fragile portion can be formed by cutting out a part of the battery case.

  Since the battery case has a fragile portion, the fragile portion can be broken by applying an external force to the fragile portion using a tool, for example. When the current cut-off mechanism is activated, electric energy remains stored in the power generation element, and the secondary battery cannot be discharged. Here, when the fragile portion is broken, the auxiliary terminal having conductivity can be brought into contact with the current path in the battery case.

  Since the fragile portion is provided at a position adjacent to the current path located on the reaction region side of the current interrupt mechanism, the auxiliary terminal can be brought into contact with the current path when the fragile portion is broken. For this reason, the current path in contact with the auxiliary terminal is electrically connected to the power generation element even after the current interruption mechanism is activated. Therefore, by bringing the auxiliary terminal into contact with the current path, the power generation element can be discharged using the auxiliary terminal, and electric energy can be prevented from being stored in the power generation element.

  Here, the outer surface of the battery case in the portion where the fragile portion is formed is covered with an insulator. For this reason, when the weak part is broken and the auxiliary terminal is inserted into the battery case, the insulator can be positioned between the auxiliary terminal and the battery case. Since the auxiliary terminal and the battery case have conductivity, the insulator is positioned between the auxiliary terminal and the battery case, so that the auxiliary terminal and the battery case are in an insulated state, and the auxiliary terminal is used to generate power. The element can be discharged.

  External electrode terminals that are electrically connected to the power generation element can be provided on the outer surface of the battery case. In this case, an insulator can be disposed between the battery case and the external electrode terminal. Here, the external electrode terminal can be held by using an insulator. If an insulator is disposed between the battery case and the external electrode terminal, the battery case and the external electrode terminal can be maintained in an insulated state, and when the auxiliary terminal is inserted into the battery case as described above, The battery case can be in an insulated state.

  An internal electrode terminal for electrically connecting the power generation element and the external electrode terminal can be provided inside the battery case. The internal electrode terminal becomes a part of the current path provided inside the battery case described above. Here, the weak part formed in a battery case can be provided in the position adjacent to an internal electrode terminal. In this case, the auxiliary terminal can be brought into contact with the internal electrode terminal when the fragile portion is broken.

  The fragile portion can be provided on at least one of the inner surface and the outer surface of the battery case. The inner surface of the battery case is a surface facing the power generation element side, and the outer surface of the battery case is a surface in contact with the insulator. If the weak part is provided on the outer surface of the battery case, the weak part can be easily grasped and the weak part can be easily broken. Here, although the fragile portion is covered with an insulator, the position of the fragile portion can be confirmed by applying an external force to the insulator and deforming the insulator.

  The weak part can be provided at the corner of the battery case. An external electrode terminal or the like is provided on the outer surface of the battery case. However, if a weak portion is provided at a corner of the battery case, the weak portion is easily broken without interfering with the external electrode terminal or the like.

  In addition to providing the battery case with a fragile portion, the insulator can also be provided with a fragile portion. Specifically, the fragile portion can be provided in the insulator at a position adjacent to the fragile portion of the battery case. The fragile portion of the insulator is formed in a shape that reduces the strength of the insulator. For example, a weak part can be formed in an insulator by notching a part of the insulator.

  A weak part can be provided in the surface on the opposite side to the surface which contacts a battery case among insulators. That is, a weak part can be provided in the surface (outer surface) exposed to the outer side of the secondary battery among insulators. By providing the weak part on the outer surface of the insulator, it becomes easy to grasp the position of the weak part provided in the insulator and the weak part provided in the battery case.

  The width of the fragile portion of the insulator can be made narrower than the width of the fragile portion of the battery case. When the fragile portion of the insulator and the battery case is broken, the opening formed by the fragile portion of the battery case (so-called rupture portion) is more than the opening formed by the fragile portion of the insulator (so-called rupture portion). It becomes easy to spread. Thereby, it becomes easy to position an insulator inside the opening part (breaking part) formed in a battery case, and it becomes easy to ensure the insulation state of an auxiliary terminal and a battery case.

  The battery case can accommodate the power generation element in a sealed state. In this case, as the current interruption mechanism, a valve that is deformed in accordance with an increase in the internal pressure of the battery case and interrupts the current path can be used. As the current interruption mechanism, for example, a fuse can be used in addition to the above-described valve.

It is an external view of a secondary battery. It is a figure which shows the internal structure of a secondary battery. It is an expanded view of an electric power generation element. It is an external view of a power generation element. It is a figure which shows the structure of a part of secondary battery when the electric current cutoff valve is not act | operating. It is a figure which shows the structure of a part of secondary battery when the electric current cutoff valve is act | operating. FIG. 7 is an enlarged view of a region A shown in FIGS. 5 and 6. The figure when discharging an electric power generation element using an auxiliary terminal is shown. In the modification of Example 1, it is sectional drawing of a battery case and an insulator. In the modification of Example 1, it is a figure explaining the position which forms a recessed part. In the modification of Example 1, it is a figure when discharging an electric power generation element using an auxiliary terminal. In Example 2, it is the schematic which shows the internal structure of a cylindrical secondary battery.

  Examples of the present invention will be described below.

  FIG. 1 is an external view of a secondary battery according to this embodiment. FIG. 2 is a schematic diagram showing the internal structure of the secondary battery. As the secondary battery 1, for example, a lithium ion battery or a nickel metal hydride battery is used. The secondary battery 1 can be used, for example, as a power source for running the vehicle.

  Specifically, by supplying the electric power of the secondary battery 1 to the motor / generator, the motor / generator can generate kinetic energy for running the vehicle. When the secondary battery 1 is mounted on a vehicle, a plurality of secondary batteries 1 can be electrically connected to form an assembled battery, and the assembled battery can be mounted on the vehicle.

  The secondary battery 1 includes a battery case 10 and a power generation element 30 accommodated in the battery case 10. The battery case 10 has a case body 11 and a lid 12 and can be formed of a metal such as aluminum.

  The case body 11 has an opening for incorporating the power generation element 30 into the case body 11, and the lid 12 closes the opening of the case body 11. The lid 12 is fixed to the case body 11 by welding or the like, and the inside of the battery case 10 is in a sealed state. In addition to the power generation element 30, an electrolytic solution is accommodated in the battery case 10. The battery case 10 is formed in a shape along a rectangular parallelepiped, and the secondary battery 1 is a so-called square battery.

  The lid 12 is provided with a valve 13. For example, the valve 13 can be formed by engraving the lid 12. The valve 13 is used for discharging gas generated inside the battery case 10 to the outside of the battery case 10. When gas is generated inside the battery case 10 and the internal pressure of the battery case 10 increases, the valve 13 changes from the closed state to the open state. The pressure when the valve 13 is changed from the closed state to the open state (operating pressure of the valve 13) can be appropriately set in consideration of the pressure resistance performance of the battery case 10 and the like.

  A liquid injection hole 14 is provided in the lid 12, and the liquid injection hole 14 is used for injecting an electrolyte into the battery case 10. The stopper 15 closes the liquid injection hole 14. When manufacturing the secondary battery 1, the lid 12 is fixed to the case body 11 after the power generation element 30 is assembled into the case body 11. Next, the electrolyte solution is injected into the battery case 10 from the solution injection hole 14, and after the electrolyte solution is injected, the solution injection hole 14 is closed by the plug 15. The valve 13 and the plug 15 (the liquid injection hole 14) are provided between the negative electrode terminal (electrode terminal) 21 and the positive electrode terminal (electrode terminal) 22.

  The negative terminal 21 and the positive terminal 22 are fixed to the lid 12. Here, an insulator is disposed between the negative electrode terminal 21 and the lid 12, and the negative electrode terminal 21 and the lid 12 are in an insulated state. Further, an insulator is disposed between the positive electrode terminal 22 and the lid 12, and the positive electrode terminal 22 and the lid 12 are in an insulated state.

  The negative electrode terminal 21 and the positive electrode terminal 22 have a portion located outside the battery case 10 and a portion located inside the battery case 10. A negative electrode tab (corresponding to an internal electrode terminal) 23 is accommodated in the battery case 10, one end side of the negative electrode tab 23 is connected to the negative electrode terminal 21, and the other end side of the negative electrode tab 23 is connected to the power generation element 30. . In the present embodiment, the negative electrode terminal 21 and the negative electrode tab 23 are configured separately, but may be configured integrally.

  A positive electrode tab (corresponding to an internal electrode terminal) 24 is accommodated in the battery case 10, one end side of the positive electrode tab 24 is connected to the positive electrode terminal 22, and the other end side of the positive electrode tab 24 is connected to the power generation element 30. . In the present embodiment, the positive electrode terminal 22 and the positive electrode tab 24 are configured separately, but may be configured integrally.

  FIG. 3 is a developed view of a part of the power generation element 30. The power generation element 30 is an element that performs charging and discharging. The power generation element 30 includes a negative electrode plate 31, a positive electrode plate 32, and a separator 33.

  The negative electrode plate 31 includes a current collector plate 31a and a negative electrode active material layer 31b. The negative electrode active material layer 31b is formed on the surface of the current collector plate 31a, and is formed on both surfaces of the current collector plate 31a. The negative electrode active material layer 31 b is formed in a partial region of the current collector plate 31 a, and the current collector plate 31 a is exposed at one end of the negative electrode plate 31. The negative electrode active material layer 31b includes a negative electrode active material, a conductive material, a binder, and the like.

  When a lithium ion secondary battery is used as the secondary battery 1, for example, carbon can be used as the negative electrode active material. Moreover, the current collecting plate 31a can be formed of copper, for example.

  The positive electrode plate 32 includes a current collector plate 32a and a positive electrode active material layer 32b. The positive electrode active material layer 32b is formed on the surface of the current collector plate 32a and is formed on both surfaces of the current collector plate 32a. The positive electrode active material layer 32 b is formed in a partial region of the current collector plate 32 a, and the current collector plate 32 a is exposed at one end of the positive electrode plate 32. As shown in FIG. 3, the portion where the current collector plate 32a is exposed is located on the opposite side to the portion where the current collector plate 31a is exposed. The positive electrode active material layer 32b includes a positive electrode active material, a conductive material, a binder, and the like.

When a lithium ion secondary battery is used as the secondary battery 1, examples of the positive electrode active material include LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiFePO ₄ , Li ₂ FePO ₄ F, LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ or Li (Li _a Ni _x Mn _y Co _z ) O ₂ can be used. Further, the current collector plate 32a can be formed of aluminum, for example.

  The separator 33 is arranged between the negative electrode plate 31 and the positive electrode plate 32, and is in contact with the negative electrode active material layer 31b and the positive electrode active material layer 32b. The electrolytic solution has soaked into the separator 33, the negative electrode active material layer 31b, and the positive electrode active material layer 32b.

  As shown in FIG. 3, the negative electrode plate 31, the positive electrode plate 32, and the separator 33 are laminated | stacked, a laminated body is comprised, and the electric power generation element 30 shown in FIG. 4 is comprised by winding a laminated body. An axis X shown in FIG. 4 indicates an axis when the laminate is wound. A region R shown in FIG. 4 (FIG. 2) is a region (referred to as a reaction region) where the negative electrode active material layer 31 b and the positive electrode active material layer 32 b face each other with the separator 33 interposed therebetween. In the reaction region R, the reactant moves between the negative electrode plate 31 and the positive electrode plate 32 in accordance with charge / discharge of the secondary battery 1 (power generation element 30).

  For example, when the secondary battery 1 as a lithium ion secondary battery is discharged, a chemical reaction that releases lithium ions (reactive substances) and electrons is performed in the negative electrode active material layer 31b. In the positive electrode active material layer 32b, a chemical reaction that absorbs lithium ions and electrons is performed. Here, lithium ions move from the negative electrode active material layer 31 b to the positive electrode active material layer 32 b through the separator 33.

  When the secondary battery 1 as a lithium ion secondary battery is charged, a chemical reaction that absorbs lithium ions and electrons is performed in the negative electrode active material layer 31b. In the positive electrode active material layer 32b, a chemical reaction that releases lithium ions and electrons is performed. Here, lithium ions move from the positive electrode active material layer 32 b to the negative electrode active material layer 31 b through the separator 33.

  As shown in FIG. 4, at one end of the power generation element 30 in the direction in which the axis X extends, only the negative electrode plate 31 (particularly, the current collector plate 31a) is wound, and the portion around which the current collector plate 31a is wound is As shown in FIG. 2, the negative electrode tab 23 is welded. The negative electrode tab 23 can be formed of the same material as that of the current collector 31a. Thereby, the negative electrode tab 23 and the current collecting plate 31a can be easily welded. Here, the portion where only the current collecting plate 31 a is wound becomes a part of a current path electrically connected to the reaction region R.

  At the other end of the power generation element 30 in the direction in which the axis X extends, only the positive electrode plate 32 (particularly, the current collector plate 32a) is wound, and the portion around which the current collector plate 32a is wound is as shown in FIG. The positive electrode tab 24 is welded. The positive electrode tab 24 can be formed of the same material as that of the current collector plate 32a. Thereby, the positive electrode tab 24 and the current collecting plate 32a can be easily welded. The method for connecting the negative electrode tab 23 and the positive electrode tab 24 to the power generation element 30 may be a method other than welding. Here, the portion where only the current collector plate 32 a is wound becomes a part of a current path electrically connected to the reaction region R.

  Due to overcharging of the secondary battery 1, gas may be generated inside the secondary battery 1 (battery case 10). This gas is generated by, for example, thermal decomposition of the electrolytic solution. Since the inside of the battery case 10 is in a sealed state, the internal pressure of the battery case 10 increases due to the generation of gas.

  Here, the secondary battery 1 has a current cutoff valve (corresponding to a current cutoff mechanism). The current cutoff valve operates when the internal pressure of the battery case 10 rises, and cuts off a current path used for charging / discharging the secondary battery 1. By operating the current cutoff valve according to the generation of gas, it is possible to suppress the current from continuing to flow through the power generation element 30.

  The structure of the current cutoff valve will be described with reference to FIG. FIG. 5 is a cross-sectional view showing a partial structure of the secondary battery 1.

  The negative electrode terminal 21 includes a terminal main body (corresponding to an external electrode terminal) 211, a terminal base (corresponding to an insulator) 212, a terminal lead (corresponding to an external electrode terminal) 213, and a fixing member 214. The terminal body 211 is electrically connected to a load or is electrically connected to another secondary battery 1. When a battery assembly is configured using a plurality of secondary batteries 1, a bus bar is connected to the terminal body 211. The bus bar is used to connect a plurality of secondary batteries 1 in series or in parallel.

  The terminal body 211 is attached to the terminal base 212, and the terminal base 212 is fixed to the lid 12. The terminal base 212 is formed of an insulating material such as resin. As the insulating material, for example, a resin such as PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) or PPS (polyphenylene sulfide) can be used. One end of the terminal lead 213 is connected to the terminal body 211, and the other end of the terminal lead 213 is connected to the fixing member 214.

  The terminal lead 213 is made of a conductive material such as metal. A terminal pedestal 212 made of an insulating material is located between the terminal lead 213 and the lid 12, and the terminal lead 213 and the lid 12 are in an insulated state. The fixing member 214 is made of a conductive material such as metal and penetrates the lid 12, the terminal base 212 and the terminal lead 213. Inside the battery case 10, an insulator is disposed between the inner wall surface of the lid 12 and the fixing member 214. The fixing member 214 and the lid 12 are in an insulated state.

  A part of the fixing member 214 located outside the battery case 10 is connected to the terminal lead 213. As a method of connecting the fixing member 214 and the terminal lead 213, for example, caulking can be used. A part of the fixing member 214 located inside the battery case 10 is connected to the current cutoff valve 25. As a method of connecting the fixing member 214 and the current cutoff valve 25, for example, welding can be used.

  The current cutoff valve 25 is made of a conductive material such as metal and has a bent portion 25a. The bent portion 25 a is connected to the negative electrode tab 23. As a method for connecting the bent portion 25a and the negative electrode tab 23, for example, welding can be used.

  When the secondary battery 1 is charged and discharged, a current flows along a current path (one example) indicated by a dotted line in FIG. For example, when charging the secondary battery 1, current (charging current) flows in the order of the negative electrode tab 23, the current cutoff valve 25, the fixing member 214, the terminal lead 213, and the terminal body 211. When the secondary battery 1 is discharged, a current (discharge current) flows in a direction opposite to the direction in which the charging current flows. That is, the current flows in the order of the terminal body 211, the terminal lead 213, the fixing member 214, the current cutoff valve 25, and the negative electrode tab 23. The current cutoff valve 25 becomes a part of a current path when charging / discharging the secondary battery 1.

  When gas is generated inside the battery case 10 due to overcharging of the secondary battery 1, the internal pressure of the battery case 10 increases. As a result, as shown in FIG. 6, the pressure P acts on the current cutoff valve 25. The pressure P is a force that pushes the current cutoff valve 25 toward the lid 12 side. When the pressure P acts on the current cutoff valve 25, the connecting portion between the current cutoff valve 25 and the negative electrode tab 23 is broken by the deformation of the current cutoff valve 25, and the current cutoff valve 25 (bending portion 25a) is separated from the negative electrode tab 23.

  When the current cutoff valve 25 changes to the state shown in FIG. 6, the state shown in FIG. 6 is maintained. That is, the current cutoff valve 25 changes irreversibly from the state shown in FIG. 5 (conduction state) to the state shown in FIG. 6 (current cutoff state). As a result, the current path can be maintained in a blocked state. The pressure P when operating the current cutoff valve 25 can be appropriately set in consideration of the pressure resistance performance of the battery case 10 and the like.

  Since the current cutoff valve 25 and the negative electrode tab 23 serve as a current path when charging and discharging the secondary battery 1, the secondary battery 1 is charged and discharged when the current cutoff valve 25 is separated from the negative electrode tab 23. Disappear. By not charging / discharging the secondary battery 1, it is possible to prevent the overcharge of the secondary battery 1 from proceeding and to suppress further increase in the internal pressure of the battery case 10.

  After the current cutoff valve 25 is activated, the secondary battery 1 cannot be discharged using the negative electrode terminal 21. When the current cutoff valve 25 operates, the secondary battery 1 is in an overcharged state, so that much electric energy remains stored in the power generation element 30.

  In the present embodiment, as will be described later, the electrical energy stored in the power generation element 30 can be output to the outside of the secondary battery 1 by using the auxiliary terminal. That is, the secondary battery 1 (power generation element 30) can be discharged using the auxiliary terminal. This configuration will be specifically described.

  As shown in FIGS. 5 and 6, at one end of the lid 12, a part of the terminal base 212 is not covered by the terminal lead 213 but exposed. FIG. 7 shows an enlarged view of the area A shown in FIGS. 5 and 6.

  At the position L, a concave portion (corresponding to a fragile portion) 212 a is formed on the upper surface of the terminal base 212, in other words, on the outer surface of the terminal base 212 exposed to the outside of the secondary battery 1. The recess 212a does not penetrate the terminal base 212. At the position L, the lid 12 is formed with a recess (corresponding to a fragile portion) 12a. The recess 12 a is formed on the surface of the lid 12 that contacts the terminal base 212.

  The recess 12a does not penetrate the lid 12. The recesses 12a and 212a are formed corresponding to each other at the position L. Specifically, the recess 12a is formed below the recess 212a at the position L. The width W1 of the recess 12a is wider than the width W2 of the recess 212a.

  By forming the recess 212a, the strength of the terminal base 212 can be reduced at the position L where the recess 212a is formed. That is, the strength of the terminal base 212 at the position L is lower than the strength of the terminal base 212 at other positions.

  Further, by forming the recess 12a, the strength of the lid 12 can be reduced at the position L where the recess 12a is formed. That is, the strength of the lid 12 at the position L is lower than the strength of the lid 12 at other positions. Here, a valve 13 is formed on the lid 12, but the strength of the recess 12 a is higher than the strength of the valve 13.

  As described above, the valve 13 is used to discharge the gas generated inside the battery case 10 to the outside of the battery case 10. Here, if the strength of the recess 12a is lower than the strength of the valve 13, the recess 12a is closed before the valve 13 changes from the closed state to the open state when the internal pressure of the battery case 10 rises due to gas generation. There is a risk of changing from a state to an open state. For this reason, in order to discharge the gas generated inside the battery case 10 from the valve 13, the strength of the recess 12 a is preferably higher than the strength of the valve 13.

  In the present embodiment, the recess 12 a of the lid 12 is covered with the terminal base 212. Since the terminal base 212 is formed of a material that can be elastically deformed, it is possible to suppress an excessive load from being applied to the concave portion 12a of the lid 12. The lid 12 is made of metal and has higher rigidity than the terminal base 212. For this reason, if the recess 12a of the lid 12 is exposed to the outside of the secondary battery 1, an excessive load may be easily applied to the recess 12a.

  In this embodiment, since the recess 12a is covered with the terminal base 212, even if an external force may act on the recess 12a, the external force can be absorbed by the elastic deformation of the terminal base 212. Thereby, it can suppress that an excessive load is applied to the recessed part 12a.

  In this embodiment, the recesses 212a and 12a are formed at the positions shown in FIG. 7, but the present invention is not limited to this. That is, it is only necessary that the strength of the terminal base 212 and the lid 12 can be reduced at the position L. For example, the recess 12 a can be formed on the inner wall surface of the lid 12 facing the inside of the battery case 10. Here, the recessed part 12a should just be formed in at least one among the outer wall surface of the lid | cover 12, and an inner wall surface.

  Moreover, the recessed part 212a can be formed in the surface which contacts the lid | cover 12 among the terminal bases 212. FIG. In this case, since the recess 212 a cannot be confirmed from the outside of the secondary battery 1, a mark can be formed at a position corresponding to the recess 212 a on the outer surface of the terminal base 212. By forming the mark, the position of the recess 212a can be confirmed. The mark only needs to be visible from the outside of the secondary battery 1. For example, a seal having a specific shape can be used as the mark.

  Here, as shown in FIG. 7, if a recess 212 a is formed on the outer surface of the terminal base 212 that is exposed to the outside of the secondary battery 1, the tip of an auxiliary terminal, which will be described later, is formed using the recess 212 a. Easy positioning. That is, the tip of the auxiliary terminal can be aligned with the position L by bringing the tip of the auxiliary terminal into contact with the recess 212a. In addition, the recessed part 212a should just be formed in at least one among the outer surface of the terminal base 212, and the surface of the terminal base 212 which contacts the lid | cover 12. FIG.

  On the other hand, the shape of the recesses 212a and 12a is not limited to the shape shown in FIG. That is, it is sufficient that the strength of the terminal base 212 and the lid 12 can be reduced at the position L, and the shapes of the recesses 212a and 12a can be set as appropriate within this range.

  In the present embodiment, the recesses 212a and 12a are formed in the terminal base 212 and the lid 12, respectively, but the present invention is not limited to this. It suffices that at least the recess 12 a is formed in the lid 12. Since the strength of the lid 12 is higher than the strength of the terminal base 212, it is preferable to reduce the strength of the lid 12. Since the terminal pedestal 212 is formed of resin or the like and has a lower strength than the lid 12, the terminal pedestal 212 does not have to be formed with the recess 212 a.

  After the current cutoff valve 25 is actuated, the auxiliary terminal 40 can be pierced at the position L of the secondary battery 1 as shown in FIG. As shown in FIG. 8, the auxiliary terminal 40 passes through the terminal pedestal 212 (recessed portion 212 a) and the lid 12 (recessed portion 12 a), and the distal end portion of the auxiliary terminal 40 is located inside the battery case 10. The tip of the auxiliary terminal 40 is in contact with the negative electrode tab 23.

  The auxiliary terminal 40 is made of a conductive material. For example, an existing component (eg, a nail) can be used as the auxiliary terminal 40. If the auxiliary terminal 40 in contact with the negative electrode tab 23 and the positive electrode terminal 22 are connected to a load (not shown), the power generating element 30 can be discharged. In FIG. 8, a current path when the power generating element 30 is discharged using the auxiliary terminal 40 is indicated by a dotted line.

  The auxiliary terminal 40 is in contact with a region of the negative electrode tab 23 that is located closer to the power generation element 30 than the connection portion with the current cutoff valve 25. Here, the positions of the recesses 212 a and 12 a may be set in advance so that the auxiliary terminal 40 can come into contact with the negative electrode tab 23 when the auxiliary terminal 40 is pierced into the secondary battery 1.

  Even when the current cutoff valve 25 is operating, the auxiliary terminal 40 can be electrically connected to the power generation element 30 by bringing the auxiliary terminal 40 into contact with the negative electrode tab 23 as described above. Thereby, the electrical energy stored in the power generation element 30 can be taken out.

  The load connected to the auxiliary terminal 40 may be anything that consumes the power of the power generation element 30. When the power generation element 30 is discharged, a current can simply be passed to the resistor as a load. Moreover, an electronic device can be operated using the electric power of the electric power generation element 30 using an electronic device as a load.

  By discharging the power generation element 30 using the auxiliary terminal 40, it is possible to prevent the secondary battery 1 from being left unattended while electrical energy is stored in the power generation element 30. Moreover, if the electronic device is operated using the electric power of the power generation element 30, the electrical energy stored in the power generation element 30 can be effectively used.

  As described above, by forming the recess 212a in the terminal base 212 and forming the recess 12a in the lid 12, the strength of the terminal base 212 and the lid 12 can be reduced in the recesses 212a and 12a. Thereby, the auxiliary terminal 40 can be easily penetrated with respect to the terminal base 212 and the lid 12.

  If the auxiliary terminal 40 is pressed against the terminal base 212 and the lid 12 without forming the recesses 212a and 12a (particularly, the recess 12a), unintended deformation may occur in the battery case 10. Further, it becomes difficult to penetrate the auxiliary terminal 40 at the predetermined position L of the battery case 10. According to this embodiment, by using the recesses 212a and 12a (particularly, the recess 12a), the battery case 10 can be easily deformed at the predetermined position L, and the auxiliary terminal 40 can be penetrated at the predetermined position L. .

  According to this embodiment, when the auxiliary terminal 40 is pushed from the outside of the battery case 10, the tip of the auxiliary terminal 40 can be aligned with the recess 212a, and the auxiliary terminal 40 can be easily penetrated at the predetermined position L. Can do. Further, by making the auxiliary terminal 40 easy to be positioned at the position L, the tip of the auxiliary terminal 40 can be easily brought into contact with the negative electrode tab 23.

  As shown in FIG. 2, the negative electrode tab 23 is arranged along a region of the power generation element 30 where only the current collector 31 a is wound. And the position L where the auxiliary terminal 40 pierces is located above the area | region where only the current collecting plate 31a was wound. For this reason, even if the auxiliary terminal 40 penetrates the negative electrode tab 23, the tip of the auxiliary terminal 40 comes into contact with a region of the power generation element 30 where only the current collecting plate 31 a is wound.

  Here, in this embodiment, the tip of the auxiliary terminal 40 is brought into contact with the negative electrode tab 23, but this is not restrictive. That is, the tip of the auxiliary terminal 40 may penetrate the negative electrode tab 23 and contact the current collector plate 31a.

  Since the outer peripheral surface corresponding to the reaction region R in the power generation element 30 is covered with the separator 33, the power generation element 30 can be obtained even if the auxiliary terminal 40 is brought into contact with the outer peripheral surface of the power generation element 30 corresponding to the reaction region R. It becomes difficult to discharge. Further, depending on the force that pushes in the auxiliary terminal 40, the auxiliary terminal 40 may cause an excessive load on the reaction region R of the power generation element 30. If an excessive load is applied to the reaction region R of the power generation element 30, it may be difficult to discharge the power generation element 30.

  According to the present embodiment, as described above, the auxiliary terminal 40 is in contact with the region of the power generation element 30 where only the current collector plate 31 a is wound, so that an excessive load is applied to the reaction region R of the power generation element 30. There is no giving.

  When the auxiliary terminal 40 is connected to the negative electrode tab 23, a terminal base 212 made of an insulating material is positioned between the lid 12 and the auxiliary terminal 40 as shown in FIG. When the auxiliary terminal 40 is connected to the negative electrode tab 23, the auxiliary terminal 40 is pierced from the outside to the inside of the battery case 10.

  Here, the terminal pedestal 212 is disposed outside the battery case 10 with respect to the lid 12, and when the auxiliary terminal 40 is inserted into the battery case 10, the terminal pedestal 212 is positioned between the auxiliary terminal 40 and the lid 12. It becomes easy to do. Thereby, the power generation element 30 can be discharged while the auxiliary terminal 40 and the lid 12 are in an insulated state.

  In this embodiment, as shown in FIG. 7, the width W1 of the recess 12a is wider than the width W2 of the recess 212a. Thereby, when the auxiliary terminal 40 penetrates the recesses 212a and 12a, the width of the opening formed in the recess 12a can be made wider than the width of the opening formed in the recess 212a. If comprised in this way, it will become easy to position the terminal base 212 between the auxiliary terminal 40 and the lid | cover 12, and it will be easy to make the auxiliary terminal 40 and the lid | cover 12 in an insulated state.

  If the auxiliary terminal 40 is attached to the position L, the power generating element 30 using the auxiliary terminal 40 can be easily discharged. The position L where the auxiliary terminal 40 is attached is located on the upper surface of the battery case 10 and at the corner of the battery case 10. Thereby, the auxiliary terminal 40 can be easily pierced into the battery case 10.

  If the auxiliary terminal 40 is pierced into a region located between the negative electrode terminal 21 and the positive electrode terminal 22, the auxiliary terminal 40 easily interferes with the electrode terminals 21 and 22, and the auxiliary terminal 40 is difficult to pierce. Therefore, if the auxiliary terminal 40 is pierced at the corner of the battery case 10 as in the present embodiment, the auxiliary terminal 40 is less likely to interfere with the electrode terminals 21 and 22, and the auxiliary terminal 40 is attached to the battery case 10. It becomes easy to pierce.

  Here, an assembled battery may be constituted by arranging a plurality of secondary batteries 1 in a predetermined direction and integrating them. Specifically, by using a pair of end plates, a plurality of secondary batteries 1 arranged in a predetermined direction are sandwiched, and both ends of a restraining member extending in a predetermined direction are fixed to the pair of end plates. Can be configured.

  In this case, since the position L is located at the corner of the assembled battery, the auxiliary terminal 40 can be easily inserted into the secondary battery 1 in which the current cutoff valve 25 is operated without disassembling the assembled battery. be able to. When the assembled battery is not disassembled, the electrode terminals 21 and 22 are positioned on the upper surface of the assembled battery by the number of the secondary batteries 1. Here, if the auxiliary terminal 40 is pierced into a region located between the electrode terminals 21 and 22, it is difficult to pierce the auxiliary terminal 40 with respect to the specific secondary battery 1 due to interference with the electrode terminals 21 and 22. turn into.

  In this embodiment, as described above, the auxiliary terminal 40 is pierced into the corner of the battery case 10, so that the auxiliary terminal 40 can be connected to the specific secondary battery 1 without disassembling the assembled battery. Can be pierced easily.

  In the present embodiment, the current cutoff valve 25 is provided for the negative terminal 21, but the current cutoff valve 25 may be provided for the positive terminal 22. Since the positive electrode terminal 22 has the same structure as that of the negative electrode terminal 21, the same structure as that of the present embodiment can be adopted when the current cutoff valve 25 is provided on the positive electrode terminal 22. The current cutoff valve 25 may be provided on at least one of the negative electrode terminal 21 and the positive electrode terminal 22.

  In the present embodiment, the current cutoff valve 25 is used as a mechanism for interrupting the current path (current cutoff mechanism), but is not limited thereto. The current interrupting mechanism only needs to be able to interrupt the current path between the negative electrode terminal 21 (or the positive electrode terminal 22) and the power generation element 30. For this reason, instead of using the current cutoff valve 25, the current path can be cut off using a fuse or the like. For example, when an overcharge of the secondary battery 1 is detected, a current can be passed through the fuse to blow the fuse.

  In the present embodiment, the auxiliary terminal 40 penetrates the lid 12, but this is not a limitation. Specifically, the auxiliary terminal 40 may penetrate the case body 11. This configuration will be described with reference to FIG. FIG. 9 is a diagram illustrating a partial configuration of the secondary battery 1.

  As shown in FIG. 9, the case body 11 has a recess 11 a. Here, the recessed part 11a is provided in the area | region facing the area | region where only the current collecting plate 31a was wound among the case main bodies 11. FIG. In other words, the recess 11a is formed at a position adjacent to the region where only the current collecting plate 31a is wound.

  Since the case main body 11 is formed along a rectangular parallelepiped, there are two surfaces facing the region where only the current collecting plate 31a is wound. Specifically, the recess 11a can be provided in any of the regions B1 and B2 shown in FIG.

  As shown in FIG. 9, the concave portion 11 a of the case body 11 is covered with an insulator 51, and the concave portion 51 a is formed in the insulator 51. The insulator 51 is fixed to the outer surface of the case body 11. Here, the recesses 11 a and 51 a are arranged side by side in the thickness direction of the case main body 11 and the insulator 51. The concave portion 51a can be omitted. Further, the positions where the recesses 11a and 51a are formed and the shapes of the recesses 11a and 51a can be set as appropriate.

  By forming the recess 11a in the case body 11 and covering the recess 11a with the insulator 51, the same effect as in the present embodiment can be obtained. In the configuration shown in FIG. 9, the auxiliary terminal 40 passes through the insulator 51 and the case body 11 and comes into contact with the current collecting plate 31 a of the power generation element 30. Depending on the position where the recess 11 a is formed, the auxiliary terminal 40 comes into contact with the negative electrode tab 23.

  Thereby, the power generation element 30 can be discharged using the auxiliary terminal 40. Moreover, since the insulator 51 is located between the auxiliary terminal 40 and the case main body 11 when the auxiliary terminal 40 penetrates the case main body 11, the auxiliary terminal 40 and the case main body 11 are in an insulated state. can do.

  In the present embodiment, the terminal base 212 formed of an insulating material covers the lid 12 at the position L where the auxiliary terminal 40 pierces, but the present invention is not limited to this. Specifically, as shown in FIG. 11, at the position L where the auxiliary terminal 40 pierces, the lid 12 may not be covered by the terminal base 212 and may be exposed. In this case, as the auxiliary terminal 40, a conductive portion 41 whose outer surface is covered with an insulating portion 42 can be used. Here, the conductive portion 41 is exposed at the tip of the auxiliary terminal 40.

  The conductive portion 41 is formed of a conductive material, and the power generating element 30 can be discharged by bringing the conductive portion 41 into contact with the negative electrode tab 23. The insulating part 42 is formed of an insulating material. When the auxiliary terminal 40 is pierced into the battery case 10, the insulating portion 42 is positioned between the conductive portion 41 and the lid 12, so that the conductive portion 41 and the lid 12 can be in an insulated state.

  A secondary battery which is Example 2 of the present invention will be described. Here, members having the same functions as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Hereinafter, differences from the first embodiment will be mainly described.

  In the first embodiment, a square battery is used as the secondary battery 1, but in the present embodiment, a cylindrical battery is used as the secondary battery 1. The structure of the cylindrical battery is shown in FIG.

  The battery case 10 accommodates a power generation element 30, and the battery case 10 includes a case body 11 and a lid 12. A region where only the current collecting plate 31 a is wound in the power generation element 30 is electrically connected to the case main body 11 via the negative electrode tab 23. Here, the case body 11 is used as a negative electrode terminal of the secondary battery 1.

  A region of the power generation element 30 in which only the current collector plate 32 a is wound is electrically connected to the current cutoff valve 25 via the positive electrode tab 24. The current cutoff valve 25 is electrically connected to the lid 12, and the lid 12 is used as a positive terminal of the secondary battery 1. The lid 12 and the case main body 11 can be fixed to each other by caulking, for example. Further, an insulator is disposed between the lid 12 and the case main body 11, and the lid 12 and the case main body 11 are in an insulated state.

  In the present embodiment, a recess can be formed in a region C of the case body 11 that faces the region where only the current collector plate 32a is wound. The area C is adjacent to the area where only the current collector plate 32a is wound. Here, similarly to the structure shown in FIG. 9, the recess 11 a can be formed in the case body 11. The recess 11 a can be covered with the insulator 51. As in the structure shown in FIG. 9, the insulator 51 can be formed with a recess 51a, or the recess 51a can be omitted.

1: secondary battery, 10: battery case, 11: case body, 12: lid, 12a: recess,
13: valve, 14: liquid injection hole, 15: stopper, 21: negative electrode terminal, 22: positive electrode terminal,
30: power generation element, 31: negative electrode plate, 31a: current collector plate, 31b: negative electrode active material layer,
32: positive electrode plate, 32a: current collector plate, 32b: positive electrode active material layer, 33: separator
211: terminal main body, 212: terminal pedestal, 212a: recess, 213: terminal lead,
214: fixing member, 25: current cutoff valve, 25a: bent portion, 40: auxiliary terminal,
41: Conductive part, 42: Insulating part

Claims (10)

A power generation element including a reaction region in which a chemical reaction according to charge and discharge is performed;
A battery case containing the power generation element and having conductivity;
A current interrupting mechanism that is accommodated in the battery case and interrupts a current path electrically connected to the power generation element;
The battery case has a fragile portion formed in a shape that reduces the strength of the battery case, and an outer surface of the battery case corresponding to the fragile portion is covered with an insulator having lower rigidity than the battery case. And
The weak portion is a current path in the battery case excluding the reaction region, and is provided at a position adjacent to a current path located on the reaction region side of the current interrupt mechanism. Secondary battery. An external electrode terminal provided on an outer surface of the battery case and electrically connected to the power generation element;
The secondary battery according to claim 1, wherein the insulator is disposed between the battery case and the external electrode terminal. The battery case is housed, and has an internal electrode terminal for electrically connecting the power generation element and the external electrode terminal,
The secondary battery according to claim 2, wherein the fragile portion is provided at a position adjacent to the internal electrode terminal.   4. The secondary battery according to claim 1, wherein the fragile portion is provided on an outer surface of the battery case that contacts the insulator. 5.   The secondary battery according to claim 1, wherein the fragile portion is provided at a corner of the battery case.   The said insulator has a weak part formed in the shape which reduces the intensity | strength of the said insulator in the position adjacent to the said weak part of the said battery case, The any one of Claim 1 to 5 characterized by the above-mentioned. Secondary battery described in 1.   The secondary battery according to claim 6, wherein the insulator has the fragile portion on a surface opposite to a surface in contact with the battery case.   The secondary battery according to claim 6, wherein a width of the fragile portion of the insulator is narrower than a width of the fragile portion of the battery case.   9. The secondary according to claim 1, wherein the fragile portion of the battery case allows the battery case to pass through an auxiliary terminal electrically connected to the power generation element. battery. The battery case houses the power generation element in a sealed state,
10. The secondary according to claim 1, wherein the current interrupt mechanism includes a valve that is deformed in response to an increase in internal pressure of the battery case and interrupts the current path. battery.

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