JP6581323B1 - In-wheel electric system - Google Patents

Abstract

In a high-frequency band, it becomes difficult to output electric power because the impedance becomes high due to the influence of the inductance inside the battery and the wiring inductance accompanying the battery serialization. In a secondary battery system in which a plurality of battery cells are connected in series, the plurality of battery cells protrude from the battery storage portion of each battery cell with the positive electrode tab and the negative electrode tab facing each other. A tab group, the tab group includes a connection surface connecting tabs between adjacent battery cells, and includes a configuration in which the connection surfaces of the positive electrode tab and the negative electrode tab are arranged in series, and faces the connection surface. And a bus bar extending along the arrangement direction of the connection surface, and the bus bar is connected to the tab group so that a current flowing direction is opposite to a current flowing through the connection surface. A secondary battery system. [Selection] Fig. 6 (a)

Description

  The present invention relates to a secondary battery system and an in-wheel electric system using the same, and more particularly to inductance reduction.

  Conventionally, studies have been made to reduce the parasitic inductance of a battery to improve the response in a high frequency band. For example, Patent Document 1 discloses a method in which a bus bar for wiring a battery has an opposing structure so that a magnetic field is canceled by a reverse current and an inductance is lowered as a battery system.

JP 2013-191400 A

  Patent Document 1 discloses a method for reducing the inductance of the battery wiring, but does not mention reduction of the inductance inside the battery. When a plurality of batteries are used in series, the inductance inside the battery increases by the number of batteries in series. In this case, the inductance inside the battery may adversely affect the entire system. Therefore, it is necessary to reduce the inductance inside the battery.

  The features of the present invention for solving the above problems are as follows, for example.

A plurality of battery cells (300) electrically connected in series with each other, a power conversion circuit unit (903) that converts DC power supplied from the plurality of battery cells into AC power, a power conversion circuit unit, and a plurality of A bus bar (511) for electrically connecting the battery cells, a plurality of battery cells, a power conversion circuit unit, a wheel portion (914) for forming a storage space for the bus bar and connecting to the shaft (920), and a plurality of The battery cell includes a first cell unit (904A) in which the plurality of battery cells are arranged in the axial direction of the shaft, and a plurality of battery cells arranged in the axial direction of the shaft and a shaft with respect to the first cell unit. circumferential and direction arranged are second cell unit (904B), is constituted by, each of the plurality of battery cells, tab group protruding from the battery storage portion of each battery cell (301,3 It has a 2), the tab group, the terminal portions connected to tab between the different poles of adjacent battery cells (304, 305)
The bus bar is opposed to the terminal portion, extends along the arrangement direction of the terminal portion, and the tab group so that the current flow direction of the bus bar is opposite to the current flowing through the connection surface. And an in- wheel electric system that is connected to the first cell unit and closer to the shaft than the second cell unit .

The present invention can provide an in-wheel electric system using a low-inductance battery system.

It is a disassembled perspective view which shows the internal structure of the electrode group 20 which concerns on one Example of this invention. It is a set figure of electrode group 20 concerning one example of the present invention. 1 is an exploded perspective view of a battery cell 100 according to an embodiment of the present invention. 1 is a set of battery cells 100 according to an embodiment of the present invention. 1 is an equivalent circuit diagram of a battery according to an embodiment of the present invention. FIG. 3 is an exploded perspective view of a high-frequency battery cell 300 according to an embodiment of the present invention. 1 is a set diagram of a high-frequency battery cell 300 according to an embodiment of the present invention. It is a figure which shows the serialization wiring of the high frequency corresponding battery which concerns on one Example of this invention. It is a figure which shows the serialization wiring of the high frequency corresponding battery which concerns on one Example of this invention. It is a figure which shows the connection structure of the serial wiring of the two battery cells 300 and the bus-bar 500 which concern on one Example of this invention. It is a figure which shows the structure at the time of wiring the bus-bar 500 which concerns on one Example of this invention. FIG. 3 is an exploded perspective view of a battery module 500 according to an embodiment of the present invention. FIG. 4 is an exploded perspective view of a battery module 500 according to an embodiment of the present invention. It is an external appearance perspective view of the battery module 500 which concerns on one Example of this invention. 1 is a motor system to which a battery according to an embodiment of the present invention is applied. It is a disassembled perspective view of the battery module 800 which serialized the battery cell 810 which concerns on one Example of this invention. It is a set figure of the battery module 800 which serialized the battery cell 810 which concerns on one Example of this invention. 1 is a power wheel system according to an embodiment of the present invention. It is a disassembled perspective view of the power wheel 901 which concerns on one Example of this invention. 1 is an overall perspective view of a power wheel 901 according to an embodiment of the present invention. 2 is an overall perspective view of an electric circuit constituting a current path from a power type battery 904 to an inverter 903. FIG. It is the top view which looked at the electric circuit of FIG. 13 from the arrow direction. It is sectional drawing which looked at the cross section by the plane S of FIG. 12 from the arrow direction. It is a whole perspective view of the 1st base 945 concerning one example of the present invention. It is a figure which shows the connection structure of the batteries 1100 which concern on one Example of this invention. The front view of the battery system which concerns on one Example of this invention. It is a perspective view of the battery system 1400 which serialized the battery module 1300 which concerns on one Example of this invention. 1 is a front view of a battery system 1400 in which battery modules 1300 according to an embodiment of the present invention are serialized.

[Example 1]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following explanation shows specific examples of the contents of the present invention, and the present invention is not limited to these explanations, and by those skilled in the art within the scope of the technical idea disclosed in this specification. Various changes and modifications are possible. In all the drawings for explaining the present invention, components having the same function are denoted by the same reference numerals, and repeated description thereof may be omitted.

  Fig.1 (a) is an exploded perspective view which shows the internal structure of the electrode group 20 which concerns on one Example of this invention. FIG. 1B is an assembled view of an electrode group 20 according to an embodiment of the present invention. Although the battery which concerns on this embodiment assumes the lithium ion battery, battery material is not restricted to it.

  As shown in FIG. 1A, the electrode group 20 includes a negative electrode 10, a positive electrode 11, and a separator 12. The negative electrode joint 13 is connected to the negative electrode 10 and serves as a current path to the outside. The positive electrode junction 14 is connected to the positive electrode 11 and serves as a current path to the outside. As shown in FIG. 1A and FIG. 1B, the two separators 12 are disposed so as to sandwich the positive electrode 11, and the negative electrode 10 is disposed on one surface of the separator 12.

The negative electrode 10, the positive electrode 11, and the separator 12 are filled with an electrolytic solution in which a lithium salt (not shown) is dissolved. Ions are conducted through this electrolytic solution. For example, in a laminate type battery, the batteries 20 are arranged in multiple layers in parallel. And the battery cell is formed by consolidating each negative electrode junction part 13 and the positive electrode junction part 14 of the electrode group 20, and integrating by welding etc. FIG.
The positive electrode 11 according to the present embodiment is applied by binding a positive electrode active material typified by a nickel-manganese-cobalt ternary positive electrode material (NMC) and a conductive additive to a foil with a binder. Is done. Moreover, the negative electrode 10 according to the present embodiment is applied by binding a negative electrode active material typified by graphite and a conductive additive to a Cu foil with a binder.

  FIG. 2A is an exploded perspective view of the battery cell 100 according to one embodiment of the present invention. FIG. 2B is an assembled view of the battery cell 100 according to one embodiment of the present invention. Although FIG. 2A shows an example in which three electrode groups 20 are stacked, the number of stacked electrode groups 20 is not limited to this.

  Moreover, although the example which applied the laminated battery is shown in a present Example, the kind of battery is not limited to a laminated battery, A square-shaped battery etc. may be sufficient.

  As shown in FIG. 2A, the separator 10 of the electrode group 20 is laminated in the same direction so as to face the negative electrode 10 of the other electrode group 20. Thereby, the stacked electrode group 20 has the separator 11 disposed on one surface and the negative electrode 10 disposed on the other surface. Furthermore, the negative electrode 10 is newly laminated so as to face the surface on which the separator 11 is disposed. Thereby, in the battery cell 100, a negative electrode is arrange | positioned on both surfaces.

  Next, the multi-layered negative electrode joint 13 and the negative electrode tab 101 are joined by welding or the like. The negative electrode tab 101 is connected to an external circuit.

  The negative electrode tab 101 is preferably a plate having a certain thickness of 0.2 mm, for example. The negative electrode tab 101 is made of copper or the like, and may be corroded by Ni plating or the like.

  Similarly, the positive electrode 11 is joined by welding or the like to the positive electrode joint portion 14 and the positive electrode tab 103 which are stacked in multiple layers.

  The positive electrode tab 103 is preferably a plate having a certain thickness of 0.2 mm, for example. The positive electrode tab 103 is made of Al or the like.

  Since the negative electrode tab 101 and the positive electrode tab 103 are hermetically sealed with a laminate, a sealing material 104 is disposed. Here, the negative electrode tab 101 (positive electrode tab 103) and the sealing material may be integrally formed. These are sandwiched from both sides by a laminate sheet 105 and sealed by heat welding.

  Thereby, since the sealing material which enables insulation and sealing is coated on the laminate sheet 105, it can adhere | attach with the sealing material 104 and can prevent the electrolyte solution from leaking.

  The battery equivalent circuit model will be described with reference to FIG.

  FIG. 3 is an equivalent circuit diagram of a battery according to an embodiment of the present invention. In order to discuss the characteristics in the high frequency band, only the equivalent circuit model related in the high frequency band is described here.

  An equivalent circuit 200 in FIG. 3 corresponds to the electrode group 20. As shown in FIG. 3, an equivalent circuit 200 derived from the electrode material of the battery in the vicinity of the tab is a parallel circuit of the battery electromotive force 201, the capacitance 202 due to the reaction of forming the electric double layer, and the charge transfer resistance 203 of the electrode active material A parallel circuit of an inductance 204 in the electrode and an inductance part resistance 205, and a DC resistance 206 that is the sum of the battery electrolyte resistance and member resistance.

  In the entire electrode, the equivalent circuit 200 derived from the electrode material is connected to the inductance 207 derived from the wiring including the tab and the like with respect to the external circuit via the resistor 208. Here, the tabs refer to the negative electrode tab 101 and the positive electrode tab 102.

  The farther from the tab, the more influenced by the inductance 209 of the foil. Therefore, in the equivalent circuit 210 derived from the electrode material in the portion z far from the tab, the foil inductance 209 is integrated by the electrode length.

The absolute value of impedance due to inductance is expressed by the following equation (1). ω is a frequency, and L is an inductance value.
Z = ωL (1)
From the formula (1), in the high frequency band, it is greatly affected by the inductance 209 and becomes high impedance. For this reason, it is difficult to supply electric power from a portion of the electrode material far from the tab. That is, it is near the tab that can respond in the high frequency band.

  Compared with the smoothing capacitor, the battery has sufficient capacity only by the capacitance due to the reaction of forming the electric double layer, and only the capacity in the vicinity of the tab is sufficient. Therefore, it is considered effective to reduce the inductance 207 of the tab.

  A method for reducing the inductance in the vicinity of the tab of the battery cell 300 will be described with reference to FIGS. 4 (a) and 4 (b). FIG. 4A is an exploded perspective view of the high-frequency battery cell 300 according to one embodiment of the present invention. FIG. 4B is an assembled view of the high-frequency battery cell 300 according to one embodiment of the present invention.

  As shown in FIGS. 4A and 4B, the negative electrode tab 301 and the positive electrode tab 302 are disposed so as to protrude in the same direction from one end surface of the laminate sheet 105. The negative electrode tab 301 and the positive electrode tab 302 are laminated in the same direction as the lamination direction of the electrode group 20. The insulating plate 303 is disposed between the negative electrode tab 301 and the positive electrode tab 302. The negative electrode tab 301 has a negative electrode terminal portion 304, and the positive electrode tab 302 has a positive electrode terminal portion 305. The negative terminal portion 304 is formed so as to be bent on the side opposite to the direction in which the positive electrode tab 302 is disposed. The positive electrode tab 302 is formed to bend in the opposite direction to the negative electrode terminal portion 304.

  The internal structure of the battery cell 300 shows a configuration in which three negative electrodes 13 and three electrode groups 20 are stacked, similarly to the battery cell 100 shown in FIG.

  Similarly to the negative electrode tab 101 and the positive electrode tab 103, the negative electrode tab 301 and the negative electrode joint portion 13, and the positive electrode tab 302 and the positive electrode joint portion 14 are connected to each other.

  The positive electrode tab 302 and the negative electrode tab 301 include protruding portions such as a negative electrode connection portion 306. Similarly, the positive electrode tab 302 includes a positive electrode tab joint 307. The shapes of the negative electrode protruding portion 306 and the positive electrode protruding portion 307 are not limited. However, when viewed from the stacking direction of the electrode group 20, the insulating properties can be ensured by being arranged at positions that do not overlap.

With such a structure, in the region where the positive electrode tab 309 and the negative electrode tab 301 overlap,
Since the current flowing through the positive electrode tab 302 and the negative electrode tab 301 flows in the opposite direction, the inductance can be reduced.

  As with the negative electrode tab 101 and the positive electrode tab 103, a sealing material 308 is disposed on the negative electrode tab 301 and the positive electrode tab 302 in order to seal with a laminate. These are sandwiched from both sides by a laminate sheet 105 and sealed by heat welding.

  The battery serialization wiring will be described with reference to FIG. FIG. 5 is a diagram showing serialized wiring of a high-frequency compatible battery according to an embodiment of the present invention.

  The terminal part 304 and the terminal part 305 function as a surface for serializing the battery cells 300. That is, the terminal portion 304 and the terminal portion 305 include regions that overlap each other in the direction perpendicular to the surfaces of the terminal portions 304 and 305. By using the terminal portions 304 and 305 as welding points for serialization, serialization is facilitated, and manufacturability is improved.

  The merit of this configuration will be described with reference to FIGS. 6 (a) and 6 (b).

  FIG. 6A is a diagram showing a connection structure between a series wiring of two battery cells 300 and a bus bar 500. FIG. 6B is a diagram showing a configuration when the bus bar 500 is wired. By simply performing serial wiring, the inductance caused by the negative terminal portion 304 and the positive terminal portion 305 increases by the number of series. Therefore, in order to reduce the inductance, it is important to reduce the inductance caused by the negative electrode tab terminal portion 304 and the positive electrode tab terminal portion 305.

  In this embodiment, as shown in FIG. 6B, the bus bar 511 is disposed so as to face the negative electrode tab terminal portion 304 and the positive electrode tab terminal portion 305 on the widest surface. As a result, the current 501 flowing through the battery in series and the current 502 flowing through the bus bar are in opposite directions, so that an inductance reduction effect can be expected.

  Thus, by using a structure that realizes inductance reduction inside the battery and inductance reduction in series, the wiring inductance 207 (see FIG. 3) can be reduced, and a high-frequency response is possible.

  Although not shown in FIG. 6A, it is desirable to dispose an insulator between the bus bar 511 and the tab when an insulation process is required.

  A configuration of a battery module 500 according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 7A is an exploded perspective view of the battery module 500 according to one embodiment of the present invention. FIG. 7B is an exploded perspective view of the battery module 500 according to one embodiment of the present invention. FIG. 7C is an external perspective view of the battery module 500 according to one embodiment of the present invention.

  As shown in FIG. 7A, the plurality of battery cells 300 are stacked such that the positive electrode tab terminal portion 305 of the predetermined battery cell 300 and the negative electrode tab terminal portion 304 of the adjacent battery cell 300 overlap each other. . The metal plate 507 is disposed so as to sandwich the battery cell 300 from both ends in the stacking direction of the plurality of battery cells 300. The metal plate 507 and the battery cell 300 are fixed by a fixing member 508 such as a screw.

  The bus bar 511 includes a negative side bus bar 504 and a positive side bus bar 505. The negative electrode side bus bar 504 and the positive electrode side bus bar 505 are provided with a load connection portion 513 and are connected to an external device or another battery module 500, respectively. As described above, the bus bar 511 is wired so as to face the negative electrode tab terminal portion 304 and the positive electrode tab terminal portion 305.

  The negative electrode side bus bar 504 is connected to the negative electrode tab terminal portion 304 via the relay conductor 510. Similarly, the positive electrode side bus bar 505 is connected to the positive electrode tab terminal portion 305 located outside on the opposite side via the relay conductor 510.

  One of the relay conductors 510 arranged on the negative electrode side is connected to the negative electrode bus bar 504, and the other is connected to the negative electrode tab terminal portion 304.

  The positive electrode bus bar 505 and the negative electrode bus bar 504 are fixed to the insulator 506 by a fixing member 515. The fixing member 515 is configured to be fixed with screws, but is not limited thereto.

  As shown in FIG. 7B, the insulator 506 is disposed between the negative electrode tab terminal portion 304 and the positive electrode tab terminal portion 305 and the bus bar 511. Thereby, insulation can be ensured.

  The insulating member 506 has a portion whose height direction is lower by the width of the relay conductor 510 at the end in order to connect the bus bar 511 and the negative terminal portion 304. Thereby, the insulator 506 can be fixed by the fixing member 508 (see FIG. 7C), and the productivity is improved. Moreover, since the edge part of the negative electrode tab terminal part 304 and the positive electrode tab terminal part 305 can be covered, the reliability of insulation improves.

  In FIG. 7C, the load connecting portion 512 and the load connecting portion 513 are arranged at the center of the bus bar 511, but the position of the load connecting portion is not limited to this position. However, the negative electrode side bus bar 504 and the positive electrode side bus bar 505 can be made common by arranging the load connecting portion 503 in the center, so that the number of parts can be reduced.

  In this embodiment, the relay conductor 510 is used, but it is not always necessary to provide it. For example, electrical connection can be ensured by inclining the negative electrode tab terminal portion 304 and the positive electrode tab terminal portion 305 connected to the bus bar 511 toward the bus bar 511. Alternatively, the bus bar 511 and the relay terminal 510 may be integrated. As a result, the number of parts can be reduced, and the number of manufacturing steps can be reduced.

  However, since the bus bar 511, the negative electrode tab terminal portion 304, and the positive electrode tab terminal portion 305 can be reliably connected by using the relay conductor 510, the connection reliability can be improved.

  FIG. 8 shows a motor system to which a battery according to an embodiment of the present invention is applied. The inverter 601 is supplied with electric power from the battery 602 and drives the motor 600. In general, when power is supplied from a battery to an inverter, it is necessary to connect a smoothing capacitor in parallel between the battery and the inverter.

  By using the low-inductance battery of this embodiment, the battery can output high-frequency power, so that smoothing capacitors can be reduced. Thereby, there exists an effect of the cost reduction by the improvement of the output density as a system, and reduction of a number of parts.

[Example 2]
In the first embodiment, an example in which the negative electrode tab 301 and the positive electrode tab 302 are used is shown. However, in this embodiment, wiring for reducing inductance when the negative electrode tab 301 and the positive electrode tab 302 are not used will be described.

  Even if it does not take the opposing tab structure of Example 1, in a battery system with few serialization, it may be possible to fall below a target inductance value. In that case, it is effective to reduce the inductance by facing only the wiring.

  FIG. 9A is an exploded perspective view of a battery module 800 in which battery cells 810 are serialized. FIG. 9B is a set of battery modules 800 in which battery cells 810 are serialized.

  The battery cell 810 includes a negative electrode tab 811 and a positive electrode tab 812 that are not opposed to each other. The positive and negative tabs are joined via a relay conductor 801 for serialization.

  As shown in FIG. 9A, the relay conductor 801 has a connection portion 802 that faces the positive and negative tabs. One connecting portion 802 is connected to the positive electrode tab 811, and the other connecting portion 802 is connected to the negative electrode tab 812, thereby connecting the positive and negative electrode tabs.

The bus bar 803 is formed and disposed so as to overlap the relay conductor 801 when viewed from the A direction in FIG. As a result, the current 804 flowing in the series direction of the battery and the current 812 flowing in the bus bar 803 are reversed in the same manner as in the first embodiment, so that the inductance can be reduced. Note that an insulator may be disposed between the bus bar 803 and the relay conductor 801. (Not shown)
In FIG. 9A, only the wiring between two batteries and the wiring part to the batteries before and after the battery are shown, but the number of series may be an arbitrary value. In the present embodiment, an example of the relay conductor 801 formed in a U-shape is shown, but the shape is not limited to the U-shape. Also, the shape of the bus bar 803 is not limited as long as the current 804 and the current 805 flowing through the bus bar 803 are in opposite directions. However, the shape shown in this embodiment has the shortest wiring distance, so that the wiring resistance can be reduced.

[Example 3]
The configuration of an electric vehicle equipped with a power wheel system is shown in FIG. The electric vehicle 900 includes a plurality of power wheels 901. The power wheel 901 includes a motor 902, an inverter 903, and a power type battery 904, and is connected in parallel to a capacity type battery 905 mounted in the vehicle body via a power line. The inverter 903, the power type battery 904, and the capacity type battery 905 are controlled by an ECU 906 ("ECU" is an abbreviation of "Electronic Control Unit"). In this embodiment, power wheels are mounted on all four wheels as a plurality of power wheels, but the number of power wheels may be any number.
Here, the motor generator 902 is an AC machine, for example, an induction machine or a synchronous machine. DC power is output from the power type battery 904 and the capacity type battery 905 to the inverter 903.
The inverter 903 converts the DC power supplied from the power type battery 904 and the capacity type battery 905 into three-phase AC power. The motor generator 902 is rotationally driven as an electric motor by the three-phase AC power output from the inverter 903. Thereby, the electric vehicle 900 travels.

  When the power supply to the motor generator 11 is insufficient with only the capacity type battery 905, for example, when the electric vehicle 900 is accelerated, power is also supplied from the power type battery 904 to the motor generator 902 via the inverter 903. . In this embodiment, the capacity-type battery 905 and the power-type battery 904 are in a simple parallel connection relationship, but a relay, a DC / DC converter, or the like that enables current distribution control between the two is arranged, and an accelerator or the like is arranged. It is also possible to control the current distribution in conjunction with the control. This is determined by the required system requirements.

  When the electric vehicle 900 is decelerated or braked, that is, when the motor generator 902 is regenerated, the AC power generated by the motor generator 902 is converted into DC power by operating the inverter 903 as a rectifier, and the power type The battery 904 and the capacity type battery 905 are charged.

  When the electric vehicle 900 is parked, the capacity type battery 905 and the power type battery 904 are charged by a charging device (not shown).

The power type battery 904 is superior in output density to the capacity type battery 905 but has a smaller energy density and capacity (Ah). Alternatively, with cost as the axis, the cost per energy (kWh) is higher than that of the capacity type battery 904, but the cost per output (kW) is lower than that of the capacity type battery 905. As such a power type battery 904, for example, a lithium ion battery or a nickel metal hydride battery is applied. Further, instead of the power type battery 905, a power storage device (ie, a power type power storage device) such as a lithium ion capacitor or an electric twentieth layer capacitor having the same high output characteristics may be used. In the following, these batteries and capacitors are collectively referred to as “power type batteries”.
Although the capacity type battery 905 is inferior in output density to the power type battery 904, the capacity type battery 905 has an excellent energy density and a large capacity (Ah). Alternatively, with cost as the axis, the cost per output (kW) is higher than that of the power battery 904, but the cost per energy (kWh) is lower than that of the power battery 904. As such a capacity type battery 905, a lithium ion battery, a lithium ion semi-solid battery, a lithium solid battery, a lead battery, a nickel zinc battery, or the like is applied.

  As described above, in this embodiment, the power type battery 904 and the capacity type battery 905 are used together, and as a whole battery to be used, the output capacity performance is optimized such as increasing the battery output while ensuring the battery capacity, Costs can be optimized for required performance (kWh, kW). Since such a system can optimize performance, it has a system configuration that can reduce the load compared to using only a capacity type battery.

  FIG. 11 is an exploded perspective view of the power wheel 901 according to the present embodiment. FIG. 12 is an overall perspective view of the power wheel 901 according to the present embodiment.

  The motor 910 includes a stator 911 and a rotor 912. The rotor 912 includes a rotor frame 914 that supports the tire 913. The shaft 920 is connected to the rotor frame 914.

  The inverter 903 converts the DC power supplied from the power type battery 904 into AC power, and transmits this AC power to the stator 911. The inverter 903 includes a U-phase power semiconductor module 930U that outputs a U-phase AC current, a V-phase power semiconductor module 930V that outputs a V-phase AC current, a W-phase power semiconductor module 930W that outputs a W-phase AC current, The capacitor module 931 for smoothing the power and the DC bus bar 932 for connecting the capacitor module 931 and the three-phase power semiconductor module are configured. The detailed structure of the inverter 903 will be described later.

  The power type battery 904 in the present embodiment is provided with six battery units 904A to 904F described in the above-described examples. The six battery units 904A to 904F are arranged in the circumferential direction around the shaft 920.

  FIG. 13 is an overall perspective view of an electric circuit constituting a current path from the power type battery 904 to the inverter 903. FIG. 14 is a top view of the electric circuit of FIG. 13 as viewed from the direction of the arrow. 15 is a cross-sectional view of the cross section taken along the plane S in FIG.

  As shown in FIG. 14, the first battery-side bus bar 941A connects a relay positive terminal 943A, which will be described later, and a positive terminal 510A of the battery unit 904A.

  The second battery-side bus bar 941B connects the negative electrode terminal 509A of the battery unit 904A and the positive electrode terminal 510B of the battery unit 904B.

  The third battery-side bus bar 941C connects the negative electrode terminal 509B of the battery unit 904B and the positive electrode terminal 510C of the battery unit 904C.

  The fourth battery-side bus bar 941D connects the negative terminal 509C of the battery unit 904C and the positive terminal 510D of the battery unit 904D.

  The fifth battery-side bus bar 941E connects the negative electrode terminal 509D of the battery unit 904D and the positive electrode terminal 510E of the battery unit 904E.

  The sixth battery-side bus bar 941F connects the negative terminal 509E of the battery unit 904E and the positive terminal 510F of the battery unit 904F.

  Each of the six bus bars such as the first battery-side bus bar 941A is formed in an arc shape centered on the shaft 920.

  The seventh battery side bus bar 941G is connected to the negative terminal 509F of the battery unit 904D. Further, the seventh battery side bus bar 941G is formed in an annular shape so as to face the first battery side bus bar 941A to the sixth battery side bus bar 941F across the insulating member 944, and is connected to the relay negative electrode terminal 943B.

  As a result, the seventh battery side bus bar 941G and the first battery side bus bar 941A to the sixth battery side bus bar 941F can be stacked to cancel the magnetic fields generated by the mutually flowing currents, thereby reducing the wiring inductance.

  The first battery-side bus bar 941A and the like are disposed between the shaft 920 and the battery units 904A to 904F. That is, the first battery-side bus bar 941A and the like are disposed on the inner peripheral side closer to the shaft 920 than the battery units 904A to 904F.

  Thereby, wiring length, such as the 1st battery side bus bar 941A, can be shortened, and wiring inductance can be made small.

  Further, the shaft 920 tends to become high temperature because heat from a rotating bearing or the like is transmitted. On the other hand, the battery units 904A to 904F tend to have strict heat resistance conditions compared to other parts. Therefore, the first battery side bus bar 941A and the like are disposed between the shaft 920 and the battery units 904A to 904F, so that an air layer functioning as a heat insulating space is formed around the first battery side bus bar 941A and the like. 904A through 904F can protect against heat from the shaft 920.

  Further, the battery units 904A to 904F are formed such that the width thereof increases as the distance from the shaft 920 increases. The width is a width in the circumferential direction with the shaft 920 as the center. Thereby, the integration rate of the battery units 904A to 904F can be improved, and the capacity of the power type battery 904 can be improved.

  Relay bus bar 942 is connected to relay bus bar 945 through relay 943. When the electric circuit from the power type battery 904 to the inverter 903 is arranged in the wheel, the wiring from the power type battery 904 to the motor 910 becomes close, and regenerative power is transmitted with little loss. On the other hand, it is necessary to take sufficient measures against over-temperature of the power type battery 904 due to overcharge or overcurrent of the power type battery 904 due to regenerative power or the like.

  Therefore, the power wheel 901 according to the present embodiment is provided with a relay 943 in the middle of the path from the power type battery 904 to the inverter 903. Also, the relay 943 according to this embodiment. For example, a mechanical relay is used. The semiconductor relay has an advantage that a wide surface can be formed and is easy to cool. However, when the power wheel 901 is not driven for a long period of time, a leakage current flows through the semiconductor relay, and the power type battery 904 is provided. There is a risk that the voltage of the lowering.

  Therefore, the relay 943 according to the present embodiment uses a mechanical relay. In addition, the mechanical relay has a complicated shape and is difficult to cool by taking the relay 943 in the same level as the power type battery 904. That is, the power type battery 904 and the relay 943 are disposed between the first base 945 and the vehicle body side base 940 shown in FIG. The relay 943 is arranged so as to overlap the power type battery 904 in the axial direction of the shaft 920. That is, the relay 943 is arranged along the circumferential direction with the battery units 904A to 904F.

  Thereby, even if it is the relay 943 with low heat-resistant temperature, it becomes easy to interrupt the heat from other heat-emitting components, and the reliability of an electrical circuit can be improved.

  FIG. 16 is an overall perspective view of the first base 945 according to the present embodiment.

  The first through hole 946 is formed to allow the shaft 920 to pass through. The second through hole 947 is formed to allow the relay-side bus bar 942 to pass therethrough. Third through hole 948 is formed to allow a control terminal extending from U-phase power semiconductor module 930U to pass through. The fourth through hole 949 is formed to pass a control terminal extending from the V-phase power semiconductor module 930V. The fifth through hole 950 is formed to allow a control terminal extending from the W-phase power semiconductor module 930W to pass through. The board fixing portion 951 is formed to fix the circuit board 952 shown in FIG.

  As shown in FIG. 15, the first base 945 forms a protruding portion 961 protruding in the axial direction, and the protruding portion 961 is supported by being in contact with a stator core 955 described later.

  The first base 945 is made of a metal material, and can prevent electromagnetic noise from the U-phase power semiconductor module 930U and the like from entering the circuit board 952.

  The first base 945 supports the six battery units 904A to 904F and the circuit board 952. The first base 945 also has an effect of radiating heat generated in the power type battery 904 and the circuit board 952.

  Further, the circuit board 952 is disposed between the battery-side bus bar such as the first battery-side bus bar 941A and the first base 945, whereby the signal wiring is shortened and the size can be reduced.

  As shown in FIG. 15, current sensor 953U detects a U-phase AC current that is input to and output from U-phase power semiconductor module 930U. Current sensor 953W detects a W-phase AC current that is input to and output from W-phase power semiconductor module 930W. Similarly, a current sensor 953V (not shown) detects a V-phase alternating current input to and output from the V-phase power semiconductor module 930V.

  As shown in FIG. 15, the stator 911 includes a coil 954 and a stator core 955 that houses the coil 954. The stator 911 faces the rotor frame 914 with the gap 956 interposed therebetween.

  The housing 957 forms a first storage portion 957A for storing the U-phase power semiconductor module 930U and the like on the inner peripheral side when viewed from the shaft 920. The housing 957 also forms a stator fixing portion 957B that fixes the stator 911 on the outer peripheral side when viewed from the shaft 920. Further, the housing 957 forms a second storage portion 957C for storing electrical components such as the current sensor 953U between the first storage portion 957A and the stator fixing portion 957B.

  The first storage portion 957A also functions as a flow path forming body through which a refrigerant for cooling the U-phase power semiconductor module 930U flows. When the first storage portion 957A functions as a flow path forming body, the heat of the stator fixing portion 957B and the second storage portion 957C can be transferred to the refrigerant. Thereby, the heat dissipation of electrical components, such as the stator 911 and the current sensor 953U, can be improved.

  As shown in FIG. 15, the hub 958 is connected to the rotor frame 914 and supported by the shaft 920 via the bearing 959. The vehicle body side base 940 is connected to the data frame 914 and supported by the shaft 920 through a bearing 960.

  When the hub 958 rotates at a high speed, the bearing 959 may become high temperature. However, the first storage portion 957A of the housing 957 functions as a flow path forming body, so that the power type in the power wheel 901 is obtained. Electric components such as the battery 904 can be protected from heat.

[Example 4]
In Example 4, a configuration capable of realizing low inductance by arranging the batteries will be described.

  FIG. 17 is a diagram illustrating a connection structure between the batteries 1100 according to the present embodiment. Since the battery 1100 does not have the opposing tab structure described in the first embodiment, the battery itself does not have a low inductance. However, as shown in FIG. 17, the bus bar 1200 is arranged in the stacking direction of the batteries 1100. By facing the bus bar 1201, it is possible to reduce the inductance of the system.

  The bus bar 1200 connects the negative electrode tab 1203 of the predetermined battery 1100 and the positive electrode tab 1204 of the battery 1100 arranged next to the predetermined battery 1100. This wiring method may be welding or fixing with screws or the like.

  Wiring is provided to face the bus bar 1201 and the bus bar 1200. As shown in FIG. 17, a current flows through bus bar 1200 and bus bar 1201 in opposite directions. Since the bus bar 1200 and the bus bar 1201 face each other, the magnetic fields cancel each other, and the inductance can be reduced as a system.

  Here, since a short circuit occurs when the bus bar comes into contact with the bus bar, an insulation plate may be used for insulation (not shown). Further, the bus bar 1200 and the bus bar 1201 may be fixed to the insulating plate. Thereby, the position shift of the bus bar due to vibration can be prevented, and the reliability of the system is improved.

  An example in which the disk-shaped battery system is applied to the structure of the counter wiring shown in FIG. 17 will be described with reference to FIGS. FIG. 18 is a front view of the battery system according to the present example. The battery system 1300 is configured in consideration of mounting efficiency when mounted in a columnar space, for example, a power wheel system. 18, 19, and 20, the insulator 1302 is shown in a transparent manner.

  As shown in FIG. 18, the battery 1100 is serialized by a bus bar 1200. In a substantially annular configuration, for example, six series batteries 1100 are used as one module. Note that the number of the batteries 1100 can be arbitrarily selected depending on the size of the battery and the circumferential length of the disk to be stored.

  The negative electrode side connection port 1303 and the positive electrode side connection port 1301 protrude from the insulating plate 1302. The insulating plate 1302 is formed in a substantially annular shape in which a portion where the battery 1100 is not arranged in the radial direction is formed in a notch shape. The annular insulating plate 1302 is disposed between the bus bar 1200 and the bus bar 1201. Further, as described above, the bus bar 1200 and the bus bar 1201 may be fixed to the insulating plate 1302. Thereby, the position shift of the bus bar due to vibration can be prevented, and the reliability of the system is improved.

    As shown in FIG. 18, when the current flows in the direction from the positive-side connection port 1301 to the negative-side connection port 1303, the direction of the magnetic field is the direction shown in FIG. On the other hand, when the disk-shaped battery system of FIG. 18 is turned upside down, the directions of current and magnetic field are opposite to those shown in FIG.

  FIG. 19 is a perspective view of a battery system 1400 in which battery modules 1300 according to this embodiment are serialized. As shown in FIG. 19, the battery module 1300 is arranged such that the direction of current is opposite to that of the adjacent battery module.

  The relay conductor 1401 connects the battery modules 1300 to each other. One end of the relay conductor 1401 is connected to the positive side connection port 1301 of a predetermined battery module, and the other end is connected to the negative side connection port 1303 of the adjacent battery module. The relay conductor 1401 can be conceived, for example, by joining copper bus bars by laser welding or the like.

  FIG. 20 is a front view of the battery system 1400 according to the present embodiment. As shown in FIG. 20, the adjacent battery modules 1400 flow in opposite directions, so that a low inductance can be realized in the entire battery system 1400 due to the magnetic field canceling effect.

  In this embodiment, an example using a battery that is not low-inductance is shown, but it is also possible to use a low-inductance battery in which the shape of the battery cell 301 shown in FIG. It is.

DESCRIPTION OF SYMBOLS 10 ... Negative electrode, 11 ... Positive electrode, 12 ... Separator, 13 ... Negative electrode junction, 14 ... Positive electrode junction, 20 ... Electrode group, 100 ... Battery cell, 101 ... Negative electrode tab, 103 ... Positive electrode tab, 104 ... Sealing material, 105 ... Laminate sheet, 200 ... Equivalent circuit, 201 ... Electromotive force of battery, 202 ... Capacitance, 203 ... Charge transfer resistance, 204 ... Inductance in electrode, 205 ... Inductance resistance, 206 ... DC resistance, 207 ... Inductance derived from wiring 208 ... Resistance derived from wiring, 209 ... Inductance of foil, 210 ... Equivalent circuit, 300 ... Battery cell, 301 ... Negative electrode tab, 302 ... Positive electrode tab, 303 ... Insulating plate, 304 ... Negative electrode tab folded portion, 305 ... Positive electrode tab Folded portion, 306 ... negative electrode tab joint, 307 ... positive electrode tab joint, 308 ... sealing material, 500 ... battery module 501 ... current, 502 ... current, 503 ... load connection, 504 ... negative electrode side bus bar, 505 ... positive electrode side bus bar, 506 ... insulating member, 507 ... metal plate, 508 ... fixing member, 510 ... relay conductor, 511 ... bus bar, 512 ... load connection part, 513 ... load connection part, 515 ... fixing member, 600 ... motor, 601 ... inverter, 602 ... battery, 800 ... battery module, 801 ... relay conductor, 802 ... connection part, 803 ... bus bar 804 ... current, 805 ... current, 810 ... battery cell, 811 ... negative electrode tab, 812 ... positive electrode tab, 901 ... power wheel, 903 ... inverter, 904 ... power type battery, 904A to 904F ... battery unit, 910 ... motor, 911 ... Stator, 912 ... Rotor, 913 ... Tire, 914 ... Rotor frame, 920 ... Shaft, 9 30U ... U-phase power semiconductor module, 930V ... V-phase power semiconductor module, 930W ... W-phase power semiconductor module, 931 ... Capacitor module, 932 ... DC bus bar, 940 ... Body side base, 941A ... First battery side bus bar, 941B ... Second battery side bus bar, 941C ... Third battery side bus bar, 941D ... Fourth battery side bus bar, fifth battery side bus bar 941E, 941F ... Sixth battery side bus bar, 941G ... Seventh battery side bus bar, 942 ... Relay side bus bar , 943 ... Relay, 943A ... Relay positive terminal, 943B ... Relay negative terminal, 944 ... Insulating member, 945 ... Relay bus bar, 946 ... First through hole, 947 ... Second through hole, 948 ... Third through hole, 949 ... 4th through-hole, 950 ... 5th through-hole, 951 ... Board fixing part, 952 ... Circuit board, 53U ... Current sensor, 953V ... Current sensor, 953W ... Current sensor, 954 ... Coil, 955 ... Stator core, 956 ... Air gap, 957 ... Housing, 957A ... First storage part, 957B ... Stator fixing part, 957C ... Second storage , 958... Hub, 959. Bearing, 960... Bearing, 961... Projection, 1100. Connection port 1303 ... negative electrode connection port 1401 ... relay conductor

Claims (4)

A plurality of battery cells (300) electrically connected to each other in series;
A power conversion circuit unit (903) for converting DC power supplied from the plurality of battery cells into AC power;
A bus bar (511) for electrically connecting the power conversion circuit unit and the plurality of battery cells;
A wheel portion (914) that forms a housing space for the bus bar and is connected to the shaft (920), the plurality of battery cells, the power conversion circuit portion,
The plurality of battery cells includes a first cell unit (904A) in which the plurality of battery cells are arranged in the axial direction of the shaft, and the plurality of battery cells are arranged in the axial direction with respect to the first cell unit. And the second cell unit (904B) arranged in the circumferential direction of the shaft,
Each of the plurality of battery cells has a tab group (301, 302) protruding from the battery storage portion of each battery cell,
The tab group has terminal portions (304, 305) that connect tabs of different polarities between adjacent battery cells,
The bus bar is opposed to the terminal portion and extends along the arrangement direction of the terminal portion, so that a current flowing direction of the bus bar is opposite to a flowing direction of the current flowing through the terminal portion. An in- wheel electric system connected to the tab group and disposed closer to the shaft than the first cell unit and the second cell unit . The in-wheel electric system according to claim 1,
Said tab group, out collision from the battery storage portion of each battery cell in a state of being opposed to the broadest aspects of the mutual positive electrode tab and negative electrode tab,
The positive electrode tab has a positive electrode terminal portion formed by bending a part of the positive electrode tab in one direction,
The negative electrode tab is an in- wheel electric system having a negative electrode terminal portion formed by bending a part of the negative electrode tab in the other direction different from the one direction . The in-wheel electric system according to claim 1 or 2,
An in-wheel electric system formed such that one or both of the first cell unit and the second cell unit has a circumferential width that increases as the distance from the shaft increases. The in-wheel electric system according to any one of claims 1 to 3 ,
The bus bar is provided in each of the first cell unit and the second cell unit and is opposed to the terminal portion, the first bus bar portion (511), the first bus bar portion of the first cell unit, and the second cell bar. A second bus bar portion (941) connecting the first bus bar portions of the cell unit,
The in-wheel electric system, wherein the second bus bar portion includes a positive electrode side second bus bar portion and a negative electrode side second bus bar portion facing the positive electrode side second bus bar portion via an insulating member.

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