JP7099008B2 - Power storage device - Google Patents

Description

The present invention relates to a power storage device including a plurality of power storage elements.

Conventionally, a power storage device including a plurality of power storage elements is known. For example, Patent Document 1 discloses a secondary battery including a laminated body formed by stacking a plurality of flat square battery cells and a pair of end plates arranged at both ends of the laminated body in the stacking direction. .. In this secondary battery, a first strain sensor for detecting the strain of the end plate is arranged on the end plate facing the battery cell at one end of the laminated body. Further, a second strain sensor for detecting the strain of the battery cell is arranged in the battery cell. The control device is operated by turning on the switch when the detection value of the first strain sensor is equal to or higher than the first threshold value and the detection value of the second strain sensor is equal to or higher than the second threshold value. The battery cell is discharged using an external resistance.

Japanese Unexamined Patent Publication No. 2016-76335

In the above-mentioned conventional secondary battery, in a laminated body composed of a plurality of battery cells, the battery cells are discharged from the battery cells at the end susceptible to an external impact according to the detection results of the two sensors. It is configured. However, in a power storage device provided with a plurality of power storage elements, for example, if one power storage element becomes unstable due to an excessive impact or the like, the other power storage elements may also be in an unsafe state. be. Therefore, when an event such as an excessive impact being applied to the power storage device occurs, it is desired to promptly shift the plurality of power storage elements included in the power storage device to a safe state. Further, for example, when the use of the power storage device should be terminated because the usage period exceeds a predetermined length, all of the plurality of power storage elements may be artificially discharged in order to prevent subsequent misuse. desirable. Further, in normal use, for example, in order to fully exert the performance of the power storage device, it is desirable to make the charge state (SOC: System of Charge) of a plurality of power storage elements uniform.

As described above, in a power storage device provided with a plurality of power storage elements, in addition to controlling the individual power storage elements in a normal time, it is necessary to perform a safe and prompt transition control to a low energy state in an emergency or the like. It is not easy to construct the composition of.

In consideration of the above-mentioned conventional problems, it is an object of the present invention to provide a power storage device provided with a plurality of power storage elements and having improved safety.

In order to achieve the above object, the power storage device according to one aspect of the present invention is a power storage device including a plurality of power storage elements, and is a normal discharge circuit provided corresponding to each of the plurality of power storage elements and a rapid discharge circuit. A discharge circuit is provided, and the normal discharge circuit and the fast discharge circuit are connected to a positive electrode terminal and a negative electrode terminal of a corresponding storage element, and the fast discharge circuit has a lower resistance than the normal discharge circuit. The positive electrode terminal and the negative electrode terminal can be electrically connected, and the fast discharge circuit electrically connects the positive electrode terminal and the negative electrode terminal when a predetermined signal is received.

According to this configuration, both a normal discharge circuit and a fast discharge circuit are arranged for each of the plurality of power storage elements. Therefore, for example, for a power storage element selected from a plurality of power storage elements, by connecting the positive electrode and the negative electrode with a normal discharge circuit, it is possible to control the power storage state of the power storage element in a normal state. Further, when the fast discharge circuit receives, for example, a signal indicating that an impact or the like has been detected or a signal indicating a discharge instruction from the user as a predetermined signal, the fast discharge circuit is a power storage element to which the quick discharge circuit is connected. Can be quickly transitioned to a safe state. Specifically, in each of the plurality of power storage elements, the positive electrode terminal and the negative electrode terminal are connected by a fast discharge circuit having a relatively small resistance. Therefore, each of the plurality of power storage elements can be safely discharged without being affected by the magnitude of the voltage of the other power storage elements. As described above, the power storage device of this embodiment is a power storage device with improved safety.

Further, in the power storage device according to one aspect of the present invention, the normal discharge circuit is a first switch capable of switching between conduction and non-conduction between the positive electrode terminal and the negative electrode terminal of the power storage element, and the positive electrode terminal or the positive electrode terminal. The second switch includes a resistance element arranged between the negative electrode terminal and the first switch, and the rapid discharge circuit can switch between conduction and non-conduction between the positive electrode terminal and the negative electrode terminal of the power storage element. And, when the rapid discharge circuit includes a conductive member arranged between the positive electrode terminal or the negative electrode terminal and the second switch and having a resistance smaller than that of the resistance element, and the rapid discharge circuit receives the predetermined signal. , The second switch may be switched from non-conducting to conductive.

According to this configuration, for example, two circuits in which a switch and a resistor are connected in series, and two circuits each having resistors having different resistance values are connected in parallel. Therefore, a normal discharge circuit and a rapid discharge circuit are realized.

Further, in the power storage device according to one aspect of the present invention, the connection state between the positive electrode terminal and the negative electrode terminal is further conducted via the normal discharge circuit, the first state, and the fast discharge circuit. The normal discharge circuit includes a changeover switch capable of switching from one state of the second state of conducting and the third state of non-conducting to the other state, and the normal discharge circuit has the positive electrode terminal in the first state. The fast discharge circuit includes a resistance element that forms a part of the conduction path between the and the negative electrode terminal, and the fast discharge circuit has a smaller resistance than the resistance element that forms a part of the conduction path in the second state. When the fast discharge circuit includes the conductive member and receives the predetermined signal, the changeover switch may be switched from the first state or the third state to the second state.

According to this configuration, for example, two resistors (resisting element or simple copper wire, etc.) connected in parallel to one of the positive electrode terminal and the negative electrode terminal of the power storage element are connected to the other of the positive electrode terminal and the negative electrode terminal. With the switch, a circuit for discharging is realized for normal and emergency situations. That is, it is possible to realize a normal discharge circuit and a rapid discharge circuit with a simple configuration.

Further, in the power storage device according to one aspect of the present invention, the fast discharge circuit may be arranged at a position corresponding to each of the plurality of power storage elements.

According to this configuration, for example, even when a plurality of fast discharge circuits are in a state of short-circuiting each storage element, and as a result, a state of generating heat is generated, the positions of the plurality of fast discharge circuits are dispersed. Therefore, the heat dissipation of each fast discharge circuit is not easily disturbed by other fast discharge circuits. Further, for example, when an impact is applied to the power storage device from a predetermined direction, the positions of the plurality of fast discharge circuits are dispersed, so that all of the plurality of fast discharge circuits may be damaged. It will be reduced.

According to the present invention, it is possible to provide a power storage device provided with a plurality of power storage elements and having improved safety.

It is a perspective view which shows the appearance of the power storage device which concerns on embodiment. It is an exploded perspective view of the power storage device which concerns on embodiment. It is a figure which shows the structural outline for discharging a plurality of power storage elements of the power storage device which concerns on embodiment. It is a circuit diagram which shows the connection relation of the power storage element, the 1st circuit and the 2nd circuit which concerns on embodiment. It is a circuit diagram which shows the connection relation of the power storage element, the 1st circuit and the 2nd circuit which concerns on the modification of embodiment. It is a figure which shows the configuration outline of the power storage device which comprises one 2nd circuit for a plurality of power storage devices. It is a figure which shows the partial cross section of the exterior body body in which two conductive plates are embedded in a wall part.

Hereinafter, embodiments of the present invention and variations thereof will be described with reference to the drawings. The embodiments and variations thereof described below are all comprehensive or specific examples. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, processes, order of processes, etc. shown in the following embodiments and modifications thereof are examples, and are not intended to limit the present invention. .. Further, among the components in the following embodiments and modifications thereof, the components not described in the independent claims indicating the highest level concept are described as arbitrary components.

It should be noted that each figure is a schematic view and is not necessarily exactly illustrated. Further, in each figure, the same reference numerals are given to substantially the same configurations, and duplicate explanations may be omitted or simplified.

Further, in the following description and drawings, the direction in which the power storage elements are arranged, the direction opposite to the long side surface of the container of the power storage elements, or the thickness direction of the container is defined as the X-axis direction. Further, the direction in which the electrode terminals are arranged in one power storage element or the direction opposite to the short side surface of the container of the power storage element is defined as the Y-axis direction. Further, the alignment direction between the main body and the lid in the exterior body of the power storage device, the arrangement direction between the power storage element and the bus bar, or the vertical direction is defined as the Z-axis direction. These X-axis directions, Y-axis directions, and Z-axis directions intersect each other (hereinafter, orthogonal to each other in the embodiments and modifications thereof). Depending on the usage mode, the Z-axis direction may not be the vertical direction, but for convenience of explanation, the Z-axis direction will be described below as the vertical direction. Further, in the following description, for example, the plus side in the X-axis direction indicates the arrow direction side of the X-axis, and the minus side in the X-axis direction indicates the side opposite to the plus side in the X-axis direction. The same applies to the Y-axis direction and the Z-axis direction.

(Embodiment)
First, the configuration of the power storage device 10 will be described. FIG. 1 is a perspective view showing the appearance of the power storage device 10 according to the embodiment. FIG. 2 is an exploded perspective view of the power storage device 10 according to the embodiment. FIG. 3 is a diagram showing an outline of the configuration for discharging a plurality of power storage elements 300 of the power storage device 10 according to the embodiment. In addition, in FIG. 2, in order to clearly show the arrangement direction and the like of the power storage element 300, the illustration of the first circuit 50, the second circuit 70, etc. shown in FIG. 3 is omitted.

The power storage device 10 is a device capable of charging electricity from the outside and discharging electricity to the outside. The power storage device 10 is a battery module used for power storage, power supply, and the like. Specifically, the power storage device 10 includes, for example, automobiles such as electric vehicles (EV), hybrid electric vehicles (HEV) or plug-in hybrid electric vehicles (PHEV), motorcycles, watercraft, snowmobiles, agricultural machinery, and construction. It is used as a battery for driving a moving body such as a machine or for starting an engine. The power storage device 10 is also used for frequency fluctuation adjustment of a power system, household storage battery equipment, an emergency power source, and the like.

As shown in FIGS. 1 and 2, the power storage device 10 includes a power storage element unit 350 including a plurality of power storage elements 300, and an exterior body 11 that covers the power storage element unit 350. In the present embodiment, the plurality of power storage elements 300 included in the power storage element unit 350 are connected in series by the bus bar 400, and the positive electrode terminal 320 of the power storage element 300 on the most positive side in the X-axis direction is the power storage element unit. It is treated as the positive electrode terminal 351 of 350. Further, the negative electrode terminal 330 of the power storage element 300 on the most negative side in the X-axis direction functions as the negative electrode terminal 352 of the power storage element unit 350. That is, the positive electrode terminal 351 is the total positive terminal of the power storage element unit 350, and the negative electrode terminal 352 is the total negative terminal of the power storage element unit 350.

The exterior body 11 is a rectangular (box-shaped) container (module case) that constitutes the exterior body of the power storage device 10. The exterior body 11 can cover the power storage element unit 350 and protect the power storage element 300 and the like from impacts and the like. The exterior body 11 is made of an insulating resin material such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), polyphenylene sulfide resin (PPS), polybutylene terephthalate (PBT), or ABS resin. The exterior body body 100 and the lid body 200 may be made of the same material or may be made of different materials.

The exterior body 11 has an exterior body body 100 that houses the power storage element unit 350, and a lid body 200 that closes the opening of the exterior body body 100. The exterior body body 100 is a member constituting the main body portion of the exterior body 11, and specifically, is a bottomed rectangular tubular housing having an opening formed in the upper portion.

The lid body 200 is a flat rectangular cover member that closes the opening of the exterior body body 100. Further, the lid body 200 is provided with a positive electrode external terminal 210 and a negative electrode external terminal 220. The power storage device 10 charges electricity from the outside and discharges electricity to the outside via the positive electrode external terminal 210 and the negative electrode external terminal 220.

Specifically, as shown in FIG. 2, the positive electrode lead plate 410 and the positive electrode external terminal 210 joined to the positive electrode terminal 351 of the power storage element unit 350 are conceptually shown by a conductive member such as a bus bar (in FIG. 2, a dotted line is conceptually shown). ) Is electrically connected. Further, the negative electrode lead plate 420 bonded to the negative electrode terminal 352 of the power storage element unit 350 and the negative electrode external terminal 220 are connected by a conductive member such as a bus bar (conceptually illustrated by a two-dot chain line in FIG. 2).

The power storage element 300 is a secondary battery (single battery) capable of charging electricity and discharging electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. .. The power storage element 300 has a flat square shape, and in the present embodiment, eight power storage elements 300 are arranged and housed in the exterior body 11 in the X-axis direction.

The power storage element 300 includes a container 310, a positive electrode terminal 320, and a negative electrode terminal 330. An electrode body (storage element), a positive electrode current collector, a negative electrode current collector, and the like are arranged inside the container 310, and an electrolytic solution (non-aqueous electrolyte) is enclosed.

The container 310 is a rectangular cuboid-shaped (square) container having long side surface portions on both side surfaces in the X-axis direction and short side surface portions on both side surfaces in the Y-axis direction. Specifically, the container 310 has a container body for accommodating an electrode body, an electrolytic solution, and the like, and a lid plate for closing the opening of the container body. That is, the container 310 has a structure in which the inside can be sealed by accommodating the electrode body or the like inside the container body and then welding or the like between the container body and the lid plate.

Further, the electrode body housed in the container 310 may have a wound shape formed by winding a negative electrode, a positive electrode, and a separator, or may have a shape in which flat electrode plates are laminated. Further, for example, the electrode body may have a structure in which long strip-shaped electrode plates are laminated in a bellows shape by repeating mountain folds and valley folds. Further, when the electrode body has a winding shape, the winding axis may be parallel to the Y-axis direction or may be parallel to the Z-axis direction. As the positive electrode active material or the negative electrode active material used for the electrode body, a known material can be appropriately used as long as it does not impair the performance of the power storage element 300. Further, the type of electrolytic solution sealed in the container 310 is not particularly limited as long as it does not impair the performance of the power storage element 300, and various types can be selected.

The positive electrode terminal 320 is an electrode terminal electrically connected to the positive electrode of the electrode body via the positive electrode current collector, and the negative electrode terminal 330 is electrically connected to the negative electrode of the electrode body via the negative electrode current collector. These are connected electrode terminals, all of which are fixed to the lid plate via an insulating member.

The power storage element 300 is not limited to the non-aqueous electrolyte secondary battery, and may be a secondary battery other than the non-aqueous electrolyte secondary battery (for example, a nickel cadmium battery, a nickel hydrogen battery, or the like). However, it may be a capacitor. Further, it may be a primary battery that can use the stored electricity without the user having to charge the battery. Further, the power storage element 300 may be a battery using a solid electrolyte. Further, the shape of the power storage element 300 is not limited to a square shape, and may be a cylindrical shape, a long cylindrical shape, a polygonal pillar shape other than a rectangular cuboid, or the like.

Further, the number of power storage elements 300 included in the power storage device 10 is not limited to 8, and for example, the number of power storage elements 300 can be adjusted according to the output voltage required for the power storage device 10.

The bus bar 400 is a conductive plate-shaped member such as a metal that is arranged above the plurality of power storage elements 300 and electrically connects the plurality of power storage elements 300 to each other. Specifically, the bus bar 400 connects the positive electrode terminal 320 of one power storage element 300 and the negative electrode terminal 330 of the other power storage element 300 in the adjacent power storage element 300. In the present embodiment, eight power storage elements 300 are connected in series by seven bus bars 400 to form a power storage element unit 350 including eight power storage elements 300.

The mode of electrical connection of the plurality of power storage elements 300 in the power storage element unit 350 is not limited to series. For example, when two subunits 300 connected in parallel are used as subunits, one subunit unit 350 may be configured by connecting four subunits in series.

The power storage device 10 configured as described above further includes a normal discharge circuit and a fast discharge circuit provided corresponding to each of the plurality of power storage elements 300. Specifically, as shown in FIG. 3, the power storage device 10 includes a first circuit 50 as a normal discharge circuit and a second circuit 70 as a fast discharge circuit. The first circuit 50 and the second circuit 70 are connected to the positive electrode terminal 320 and the negative electrode terminal 330 of the corresponding power storage element 300.

The first circuit 50 is a discharge circuit connected to each of the plurality of power storage elements 300 in order to make the charging state of the plurality of power storage elements 300 uniform during normal use of the power storage device 10. That is, in the present embodiment, the power storage device 10 is provided with eight first circuits 50 corresponding to the eight power storage elements 300. The eight first circuits 50 are arranged on, for example, the control board 40 included in the power storage device 10. The control board 40 is housed in, for example, a space inside the lid 200 above the power storage element unit 350.

The second circuit 70 rapidly discharges the corresponding power storage element 300 when the power storage device 10 becomes unstable or is likely to become unstable due to, for example, excessive impact or vibration. It is a circuit for discharging. The second circuit 70 is also used when, for example, the power storage element 300 is discharged at the end of use of the power storage device 10. In the present embodiment, as shown in FIG. 3, the second circuit 70 is arranged at a position corresponding to each of the plurality of power storage elements 300. More specifically, in the present embodiment, one connected to the positive electrode terminal 320 and the negative electrode terminal 330 of the power storage element 300 at a position above each of the eight power storage elements 300 provided in the power storage device 10. The second circuit 70 is arranged.

The plurality of first circuit 50 and second circuit 70 operate in response to the control signal transmitted from the control unit 550. The control unit 550 is a device that controls charging / discharging of a plurality of power storage elements 300 included in the power storage element unit 350. The control unit 550 monitors, for example, the charging state of each storage element 300, and controls the operation of one or more first circuits 50 based on the monitoring result to make the charging state of the plurality of storage elements 300 uniform. do.

Further, the control unit 550 controls the operation of the plurality of second circuits 70 included in the power storage device 10 based on the detection result received from the detection unit 500, for example, so that the control unit 550 controls the operation of the plurality of second circuits 70 included in the power storage device 10. To discharge rapidly.

The detection unit 500 is an example of a detection unit that detects a change in the state of the power storage device 10. In the present embodiment, the detection unit 500 detects a change in the shape of at least a part of the power storage device 10. More specifically, two conductive plates 510 and 520 arranged so as to double surround the power storage element unit 350 are connected to the detection unit 500 inside the exterior body 11. Although not shown in FIG. 2 and the like, the inner conductive plate 520 of the two conductive plates 510 and 520 and the power storage element unit 350 are configured to be electrically insulated by an insulating film or the like. Has been done.

These conductive plates 510 and 520 are members for detecting that the state of the power storage device 10 has changed. In the present embodiment, for example, when the exterior body 11 is deformed or damaged by applying pressure or impact to the power storage device 10, the conductive plates 510 and 520 come into contact with each other, and the state of the power storage device 10 is changed. Is detected. Specifically, in the detection unit 500, when the conductive plate 510 and the conductive plate 520 come into contact with each other, a current flows through the circuit including the conductive plates 510 and 520 (the resistance value becomes equal to or less than a predetermined value). ) Is detected. As a result, the detection unit 500 detects that the conductive plate 510 and the conductive plate 520 are in contact with each other.

The detection result by the detection unit 500 is notified to the control unit 550, and the control unit 550 controls the operation of the eight second circuits 70 corresponding to the eight power storage elements 300. As a result, each of the eight power storage elements 300 is in a state of being rapidly discharged.

The above-mentioned control function by the control unit 550 is realized by, for example, a control device provided in a device such as an automobile equipped with a power storage device 10. Further, the above control function may be realized by an electronic circuit housed in the exterior body 11. Further, the function of controlling the plurality of first circuits 50 and the function of controlling the plurality of second circuits 70 may be realized by electronic circuits that are separate from each other. In this case, the function of controlling the plurality of first circuits 50 may be realized by, for example, an electronic circuit formed on the control board 40.

The above-mentioned normal discharge operation by the first circuit 50 and the rapid discharge operation by the second circuit 70 will be described with reference to FIG. FIG. 4 is a circuit diagram showing a connection relationship between the power storage element 300, the first circuit 50, and the second circuit 70 according to the embodiment. In FIG. 4, the main circuit for charging / discharging electricity between the plurality of power storage elements 300 included in the power storage device 10 and the outside is omitted. This also applies to the circuit diagram shown in FIG. 5, which will be described later.

As shown in FIG. 4, the first circuit 50 and the second circuit 70 are connected in parallel to each of the plurality of power storage elements 300. In the present embodiment, the first circuit 50 includes a first switch 51 and a resistance element 52 connected in series between the positive electrode terminal 320 and the negative electrode terminal 330 of the power storage element 300. That is, the first switch 51 is a switch for switching between conduction and non-conduction between the positive electrode terminal 320 and the negative electrode terminal 330 of the power storage element 300. In FIG. 4, the resistance element 52 is arranged between the negative electrode terminal 330 and the first switch 51, but the resistance element 52 may be arranged between the positive electrode terminal 320 and the first switch 51. good.

In the present embodiment, the second circuit 70 includes a second switch 71 and a conductive member 72 connected in series between the positive electrode terminal 320 and the negative electrode terminal 330 of the power storage element 300. The conductive member 72 is a member having a smaller resistance than the resistance element 52 of the first circuit 50, and is realized by, for example, a copper wire having a predetermined wire diameter and length. Further, the material of the wire rod as the conductive member 72 is not limited to copper, and may be, for example, stainless steel material (SUS) or nichrome. The conductive member 72 may be a resistance element having a resistance value smaller than that of the resistance element 52.

With respect to the first circuit 50 configured as described above, the control unit 550 acquires, for example, the voltage detection result of each storage element 300, and is the first of the first circuit 50 corresponding to the storage element 300 to be discharged. The switch 51 is switched from off to on. As a result, the storage element 300 is short-circuited via the resistance element 52 and the first switch 51, and the storage capacity is consumed (that is, discharged). As a result, the charging state of the plurality of power storage elements 300 can be made uniform. During normal use of the power storage device 10, such forced discharge of each power storage element 300 using the first circuit 50 is performed.

Further, for example, when a device such as an automobile equipped with the power storage device 10 causes a collision accident and an excessive impact or vibration is applied to the power storage device 10, a part of the power storage device 10 (the present embodiment). Then, the shape of the exterior body 11) changes. As a result, the conductive plates 510 and 520 (see FIGS. 2 and 3), which are normally arranged apart from each other, come into contact with each other. When the detection unit 500 detects the contact between the conductive plates 510 and 520, the detection unit 500 transmits a signal corresponding to the detection result to the control unit 550. When the control unit 550 receives the signal, the control unit 550 transmits a predetermined signal (control signal) to the second circuit 70 configured as described above. Specifically, the control unit 550 transmits a control signal to all of the eight second circuits 70 included in the power storage device 10. As a result, in each of the eight second circuits 70, the second switch 71 is switched from off to on. As a result, each of the eight storage elements 300 is short-circuited by the low resistance circuit, and the storage capacity is rapidly consumed (that is, rapid discharge). As a result, all the power storage elements 300 included in the power storage device 10 quickly shift to the low energy state, and the possibility of unsafe events such as heat generation is reduced. In addition to or in place of the detection result from the detection unit 500, the control unit 550 transmits, for example, a control signal for rapid discharge to each of the plurality of second circuits 70 according to an instruction from the user. You can also do it. That is, not in an emergency such as a collision accident, but when the use of the power storage device 10 is completed, all of the plurality of power storage elements 300 included in the power storage device 10 are discharged according to the intention of the user (including the operator). Is also possible. That is, according to the power storage device 10 according to the present embodiment, it is possible to manage the charging state of the plurality of power storage elements 300 included in the power storage device 10 until the end of use.

As described above, the power storage device 10 according to the present embodiment is a power storage device 10 including a plurality of power storage elements 300, and is a normal discharge circuit provided corresponding to each of the plurality of power storage elements 300. A first circuit 50 and a second circuit 70, which is a fast discharge circuit, are provided. The first circuit 50 and the second circuit 70 are connected to the positive electrode terminal 320 and the negative electrode terminal 330 of the corresponding power storage element 300. The second circuit 70 can electrically connect the positive electrode terminal 320 and the negative electrode terminal 330 in a state where the resistance is lower than that of the first circuit 50. When the second circuit 70 receives a predetermined signal, the positive electrode terminal 320 and the negative electrode terminal 330 are electrically connected to each other.

As described above, in the power storage device 10 according to the present embodiment, both the normal discharge circuit and the fast discharge circuit (first circuit 50 and second circuit 70) are arranged for each of the plurality of power storage elements 300. There is. Therefore, for example, by connecting the positive electrode and the negative electrode to the power storage element selected from the plurality of power storage elements 300 by the first circuit 50, it is possible to control the charging state of the power storage element 300 in the normal state. Further, when the second circuit 70, which is a fast discharge circuit, receives, for example, a signal such as impact detection or a signal based on an instruction from the user as a predetermined signal, the energy storage element 300 to which the second circuit 70 is connected is connected. Can be quickly transitioned to a low energy state (ie, a safe state). Specifically, in each of the plurality of power storage elements 300, the positive electrode and the negative electrode are connected by a second circuit 70 having a relatively small resistance. Therefore, each of the plurality of power storage elements 300 can safely discharge without being affected by the magnitude of the voltage of the other power storage elements 300.

Further, by simply selecting either the first circuit 50 or the second circuit 70, normal discharge can be performed, or rapid discharge can be performed when an unsafe event occurs. That is, with a simple configuration, the safety of the power storage device 10 can be ensured in an emergency such as a collision accident while maintaining or improving the performance of the power storage device 10 in a normal time.

Further, for example, at the end of use of the power storage device 10, the user can intentionally discharge each of all the power storage elements 300 included in the power storage device 10. Therefore, for example, it is possible to prevent the power storage device 10 that should not be used from being accidentally diverted to another device (misuse). As described above, the power storage device 10 according to the present embodiment is a power storage device with improved safety.

Further, in the power storage device 10 according to the present embodiment, the first circuit 50 has a first switch 51 capable of switching between conduction and non-conduction between the positive electrode terminal 320 and the negative electrode terminal 330 of the power storage element 300, and a positive electrode. A resistance element 52 arranged between the terminal 320 or the negative electrode terminal 330 and the first switch 51 is included. The second circuit 70 includes a second switch 71 capable of switching between conduction and non-conduction between the positive electrode terminal 320 and the negative electrode terminal 330 of the power storage element 300, and the positive electrode terminal 320 or the negative electrode terminal 330 and the second switch 71. A conductive member 72 having a resistance smaller than that of the resistance element 52 is included, which is arranged between them. The second circuit switches the second switch 71 from non-conducting to conductive when it receives a predetermined signal.

As described above, in the present embodiment, for example, two circuits in which a switch and a resistor are connected in series, and two circuits each having resistors having different resistance values are connected in parallel. Then, the first circuit 50 and the second circuit 70 are realized. That is, the first circuit 50 and the second circuit 70, which are discharge circuits for normal use and rapid use, are realized with a simple configuration.

Further, in the power storage device 10 according to the present embodiment, the second circuit 70 is arranged at a position corresponding to each of the plurality of power storage elements 300. Specifically, for example, as shown in FIG. 2, a second circuit 70 for rapidly discharging the power storage element 300 is arranged above each power storage element 300.

According to this configuration, for example, even when a plurality of second circuits 70 are in a state of short-circuiting each storage element 300, and as a result, a state of generating heat is generated, the plurality of second circuits 70 are in a state of short-circuiting. Since the positions are dispersed, the heat dissipation of each second circuit 70 is less likely to be hindered by the other second circuit 70. Further, it is unlikely that a problem will occur due to the concentration of heat from the plurality of second circuits 70. Further, for example, when an impact is applied to the power storage device 10 from a predetermined direction, the positions of the plurality of second circuits 70 are dispersed, so that all of the plurality of second circuits 70 are damaged. The possibility is reduced. That is, in an emergency such as a collision accident, there is a high probability that at least a part of the rapid discharge functions of the plurality of power storage elements 300 included in the power storage device 10 will be free from damage due to impact or the like. Therefore, in an emergency such as a collision accident, the possibility that the power storage device 10 shifts to a safe state at an early stage is improved.

Although the power storage device 10 according to the embodiment has been described above, the power storage device 10 may include a first circuit and a second circuit having a mode different from the modes shown in FIGS. 2 to 4. Therefore, a modified example of the first circuit and the second circuit for discharging the plurality of power storage elements 300 will be described below, focusing on the difference from the above embodiment.

(Modification example)
FIG. 5 is a circuit diagram showing a connection relationship between the power storage element 300, the first circuit 50a, and the second circuit 70a according to the modified example of the embodiment.

As shown in FIG. 5, the power storage device 10a according to this modification is a first circuit 50a, which is a normal discharge circuit, and a first circuit 50a, which is a rapid discharge circuit, provided corresponding to each of the plurality of power storage elements 300. The two circuits 70a are provided. In this modification, the first circuit 50a and the second circuit 70a are different from the above-described embodiment in that the switching from one of conduction and non-conduction to the other is performed by one switch.

Specifically, in the power storage device 10a according to the present modification, the connection state between the positive electrode terminal 320 and the negative electrode terminal 330 is conducted via the first circuit 50a and the second circuit 70a. A changeover switch 81 capable of switching from one state of the second state of conducting and the third state of non-conducting to the other state is provided. The first circuit 50a includes a resistance element 52 that forms a part of a conduction path between the positive electrode terminal 320 and the negative electrode terminal 330 in the first state. The second circuit 70a includes a conductive member 72 having a resistance smaller than that of the resistance element 52, which forms a part of the conduction path in the second state. When the second circuit 70a receives a predetermined signal, the second circuit 70a switches the changeover switch 81 from the first state or the third state to the second state.

That is, when the control unit 550 transmits a predetermined signal (control signal) to the second circuit 70a in response to the detection result by the detection unit 500 or an instruction from the user, the control unit 550 is connected to the second circuit 70a. In the power storage element 300, discharge occurs in a low resistance state via the second circuit 70a.

As described above, in the power storage device 10 according to the present modification, for example, two resistors connected in parallel to one of the positive electrode terminal 320 and the negative electrode terminal 330 of the power storage element 300 (in this modification, the resistance element 52 and the conductivity). A discharge circuit for normal use and rapid use is realized by the member 72) and the changeover switch 81 connected to the other of the positive electrode terminal 320 and the negative electrode terminal 330. That is, it is possible to realize the first circuit 50a which is a normal discharge circuit and the second circuit 70a which is a fast discharge circuit with a simple configuration.

During normal use of the power storage device 10a, the first circuit 50a switches the changeover switch 81 from one of the first state and the third state to the other in response to the control signal from the control unit 550. As a result, the charging state of the plurality of power storage elements 300 can be made uniform in the normal state. That is, the changeover switch 81 constitutes a part of the first circuit 50a when operating the first circuit 50a, and constitutes a part of the second circuit 70a when operating the second circuit 70a. I can say.

(Other embodiments)
Although the power storage device 10 according to the embodiment of the present invention and the modified example thereof has been described above, the present invention is not limited to the above-described embodiment and the modified example thereof.

For example, when the second circuit 70 according to the embodiment is put into a conductive state (that is, when the second switch 71 is switched from off to on), the first circuit 50 may be in a conductive state. That is, when the second switch 71 is switched from off to on, the first switch 51 may also be switched from off to on, or may be maintained in the on state. That is, when the fast discharge using the second circuit 70 should be performed according to the control signal from the control unit 550, the fast discharge by the second circuit 70 is not hindered even if the first circuit 50 is in a conductive state.

Further, as a configuration for forcibly and collectively discharging the plurality of power storage elements 300 included in the power storage device 10, it is conceivable to provide one second circuit for the plurality of power storage elements 300.

FIG. 6 is a diagram showing an outline of the configuration of a power storage device 10 including one second circuit 170 for a plurality of power storage elements 300.

In the power storage device 10 shown in FIG. 6, a second circuit 170 including a second switch 171 and a conductive member 172 connected in series is connected in series to a power storage element unit 350 composed of eight power storage elements 300. The conductive member 172 is a member having a smaller resistance than the resistance element 52 of the first circuit 50. In this configuration, for example, in an emergency such as a collision accident, when the conductive plates 510 and 520 come into contact with each other, the detection unit 500 has a current flowing through the circuit including the conductive plates 510 and 520 (the resistance value is a predetermined value). The following is detected). In this case, the control unit 550 transmits a predetermined signal (control signal) to the second circuit 170. The second circuit 170 switches the second switch 171 from off to on in response to this control signal. As a result, the plurality of (8 in FIG. 6) power storage elements 300 constituting the power storage element unit 350 are collectively and forcibly discharged. Further, at the end of use of the power storage device 10, the second switch 171 can be switched from off to on according to the user's intention, that is, all of the plurality of power storage elements 300 included in the power storage device 10 can be discharged. Is.

Further, the conductive plates 510 and 520, which are members for detecting the change in the state of the power storage device 10, may be embedded in the wall portion of the exterior body 11, for example. FIG. 7 is a diagram showing a partial cross section of the exterior body main body 101 in which the conductive plates 510 and 520 are embedded in the wall portion.

As shown in FIG. 7, the conductive plates 510 and 520 are arranged so as to face each other and to be separated from each other between the inner surface 101a and the outer surface 101b of the wall portion of the exterior body body 101. This makes it easier to detect that the exterior body body 101 is deformed, for example, when the exterior body body 101 is impacted. Further, since the entire conductive plates 510 and 520 are protected by the exterior body body 101, deterioration of the conductive plates 510 and 520 is suppressed, for example. Further, for example, erroneous detection due to a conductive foreign substance entering between the conductive plates 510 and 520 is less likely to occur.

When the conductive plates 510 and 520 are embedded in the wall portion of the exterior body 101, for example, the exterior body 101 including the conductive plates 510 and 520 is formed by insert molding using a resin material and the conductive plates 510 and 520. May be produced. Further, the exterior body body 101 has a double structure of an inner box forming the inner surface 101a and an outer box forming the outer surface 101b, and the conductive plates 510 and 520 are opposed to each other between the inner box and the outer box. They may be arranged apart from each other.

Further, the conductive plates 510 and 520, which are members for detecting a change in the state of the power storage device 10, need not be arranged so as to cover the entire circumference of the power storage element unit 350. For example, if the portion of the power storage device 10 that is likely to be impacted is known in advance depending on the installation location or the posture at the time of installation, the conductive plates 510 and 520 face each other only at the position corresponding to the portion. It may be arranged so as to be separated from each other.

Further, the method for detecting the change in the state of the power storage device 10 is not limited to the method using the above-mentioned two conductive plates 510 and 520. For example, by arranging a pressure sensor, a contact sensor, an acceleration sensor, or the like at any position of the power storage device 10, an excessive impact or vibration is applied to the power storage device 10, or at least the power storage device 10 is subjected to an excessive impact or vibration. It may be detected that a part is deformed.

Further, the power storage device 10 acquires, for example, a detection result regarding impact or vibration from a device such as an automobile equipped with the power storage device 10, and rapidly discharges a plurality of power storage elements 300 according to the acquired detection result. You may. That is, the power storage device 10 does not need to have a detection unit such as a sensor for controlling the operation of the second circuit 70, for example.

Further, the exterior body 11 holding the plurality of power storage elements 300 does not need to have a case-like shape for accommodating the plurality of power storage elements 300. For example, the exterior body may be configured by a pair of end members arranged at both ends of the plurality of power storage elements 300 and a connecting member connecting the pair of end members.

Further, a form constructed by arbitrarily combining the components included in the above-described embodiment and its modifications is also included in the scope of the present invention.

The present invention can be applied to a power storage device or the like provided with a plurality of power storage elements such as a lithium ion secondary battery.

10, 10a Power storage device 50, 50a First circuit 51 First switch 52 Resistance element 70, 70a, 170 Second circuit 71, 171 Second switch 72, 172 Conductive member 81 Changeover switch 300 Power storage element 320, 351 Positive electrode terminal 330, 352 Negative terminal

Claims (4)

A power storage device equipped with multiple power storage elements.
A normal discharge circuit and a quick discharge circuit provided corresponding to each of the plurality of power storage elements are provided.
The normal discharge circuit and the fast discharge circuit are connected to the positive electrode terminal and the negative electrode terminal of the corresponding power storage element.
The fast discharge circuit can electrically connect the positive electrode terminal and the negative electrode terminal in a state of lower resistance than the normal discharge circuit.
The fast discharge circuit is a power storage device that electrically connects the positive electrode terminal and the negative electrode terminal when a signal based on the detection of a change in the shape of a part of the power storage device is received. The normal discharge circuit includes a first switch capable of switching between conduction and non-conduction between the positive electrode terminal and the negative electrode terminal of the power storage element, and between the positive electrode terminal or the negative electrode terminal and the first switch. Includes resistance elements located in
The fast discharge circuit includes a second switch capable of switching between conduction and non-conduction between the positive electrode terminal and the negative electrode terminal of the power storage element, and between the positive electrode terminal or the negative electrode terminal and the second switch. Includes a conductive member arranged in the above, which has a smaller resistance than the resistance element.
The power storage device according to claim 1, wherein the fast discharge circuit switches the second switch from non-conducting to conductive when the signal is received. Further, the connection state between the positive electrode terminal and the negative electrode terminal is in the first state of conducting through the normal discharge circuit, the second state of conducting through the fast discharge circuit, and the non-conducting state. Equipped with a changeover switch that can switch from one of the third states to the other,
The normal discharge circuit includes a resistance element that forms a part of a conduction path between the positive electrode terminal and the negative electrode terminal in the first state.
The fast discharge circuit includes a conductive member having a resistance smaller than that of the resistance element, which forms a part of the conduction path in the second state.
The power storage device according to claim 1, wherein the fast discharge circuit switches the changeover switch from the first state or the third state to the second state when the signal is received. The power storage device according to any one of claims 1 to 3, wherein the fast discharge circuit is arranged at a position corresponding to each of the plurality of power storage elements.

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