Battery assembly, electric vehicle equipped with the battery assembly, and power storage device

Abstract

In order to protect an electronic circuit block having a voltage detection circuit from the influence of exhaust gas at high temperature and high pressure and achieve high safety, a battery assembly includes a battery laminate formed by laminating a plurality of battery cells, a pair of end plates (3) disposed at both ends in the lamination direction of the battery laminate, a tie bar (4) that connects the pair of end plates (3) to fix the battery cells, and an electronic circuit block (6) on which a voltage detection circuit for detecting the voltage of the battery cells is mounted. The electronic circuit block (6) is disposed on the surface of the end plate (3).

Description

Technical Field

[0001] The present invention relates to a battery module formed by connecting a plurality of battery cells, an electric vehicle, and a power storage device including the battery module, and particularly to a battery module for a motor that drives a vehicle such as a hybrid vehicle, a fuel cell vehicle, an electric vehicle, or an electric motorcycle, or a battery module that supplies power to a high-current power source used for power storage applications such as household or industrial use, and an electric vehicle and a power storage device including the battery module.

[0002] In this specification, the "battery module" is used in a broad sense to refer to all battery modules in which end plates are arranged on both end faces of a plurality of battery cells and a pair of end plates are connected by a tightening strip, and which include a voltage detection circuit for detecting the voltage of the battery cells, and also include, for example, a "battery pack" that includes a charge / discharge circuit of the battery and a control circuit that does not include a battery. Background Art

[0003] A battery module including a plurality of battery cells is used in battery modules for vehicles such as hybrid vehicles and electric vehicles, power sources for power storage systems such as industrial and household use (for example, refer to Patent Document 1).

[0004] An example of such a battery module is shown in the Figure 12 exploded perspective view. In the battery module 900 shown in this figure, a plurality of battery cells 901 are stacked to form a battery stack 902. End plates 903 are arranged on both end faces of the battery stack 902, and a pair of end plates 903 are fastened by a tightening strip 904 to fix the battery cells 901. In each battery cell 901, a pair of positive and negative electrode terminals 911 are arranged on a terminal surface 910 on the upper surface. The positive and negative electrode terminals 911 are electrically connected by a bus bar 914, and the battery cells 901 are connected in series and in parallel.

[0005] In addition, a gas passage 905 for guiding the exhaust gas of an exhaust valve 901a from the terminal surface 910 on the upper surface of the battery cell 901 is arranged on the upper surface of the battery stack 902. The gas passage 905 is provided with an inflow hole (not shown) for the exhaust gas ejected from the exhaust valve 901a of each battery cell 901 to flow into the interior. Moreover, a circuit board 906 connected to each battery cell 901 is arranged on the upper surface of the gas passage 905.

[0006] The gas passage is provided to discharge the high-temperature and high-pressure exhaust gas discharged from the exhaust valve of the battery cell to the outside. The exhaust valve opens when the internal pressure rises to a set value, preventing the rupture of the battery case. The exhaust valve opens when it detects an abnormally high internal pressure of the battery. However, due to overcharging, over-discharging, and then internal short circuits, a combustion phenomenon occurs inside the battery cell, causing the internal pressure of the battery cell to rise abnormally. Therefore, the exhaust gas becomes high-temperature and high-pressure. The high-temperature and high-pressure exhaust gas ejected from the battery cell has adverse effects such as burning of surrounding components. The gas passage is arranged on the terminal surface of the battery cell to smoothly discharge the exhaust gas to the outside. However, a circuit board for mounting electronic components is also arranged on the terminal surface of the battery cell, and this circuit board is also affected by adverse effects such as burning of the board due to the high-temperature and high-pressure exhaust gas. Moreover, a voltage detection circuit for implementing the protection circuit of the battery cell is installed on the circuit board, and these electronic components are also affected by the adverse effects caused by the high-temperature and high-pressure exhaust gas. In addition, a connector and a lead for connecting the battery cell to the circuit board are also arranged on the terminal surface of the battery cell. However, the high-temperature and high-pressure exhaust gas causes the connector and the lead to burn, and the heat of this combustion becomes the reason for the battery cell to smoke and catch fire in a chain reaction, reducing safety.

[0007] The exhaust gas is abnormally high-temperature and high-pressure, so it is difficult for the gas passage to completely discharge the gas to the outside. The circuit board is separated from the terminal surface of the battery cell due to the gas passage, but there is a possibility of further increasing the thermal damage such as burning of the circuit board due to the exhaust gas leaking from the gas passage. Moreover, foreign matters such as metal sheets inside the battery cell are contained in the exhaust gas, and these foreign matters also become the reasons for short circuit failures of the electronic circuits on the circuit board.

[0008] Moreover, in almost all applications, the battery assembly is expected to be miniaturized as a whole without exception. The purpose is to increase the charge-discharge capacity per unit volume and improve performance. However, since multiple components are arranged on the terminal surface of the battery cell, it is difficult to reduce the height from the terminal surface. Specifically, as the components arranged on the terminal surface, there are a gas passage for discharging the exhaust gas, electrode terminals protruding from the terminal surface, a bus bar of a metal plate for connecting adjacent electrode terminals to each other, a circuit board for mounting electronic components, a lead for connecting the circuit board and the battery cell, an insulating material for insulating the components from the high-voltage battery laminate, etc. Most of these components need to be arranged without interfering with each other.

[0009] For a battery assembly in which a plurality of components such as a gas passage, a circuit board, and leads are arranged on the terminal surface of a battery cell, it is difficult to reduce the height of the battery assembly and miniaturize it only by improving the component arrangement. The circuit board substantially becomes a drawback that increases the volume of the battery assembly, especially the height. On the other hand, if the circuit board is made thinner and miniaturized, the disadvantage that the heat energy of the heat-generating components mounted on the circuit board cannot be efficiently dissipated becomes significant. Since heat-generating components such as semiconductor elements and discharge resistors are mounted on the circuit board, it is extremely important to efficiently dissipate heat energy and keep the temperature rise of the heat-generating components below the set temperature.

[0010] Prior art documents

[0011] Patent documents

[0012] Patent Document 1: International Publication No. 2014 / 024452 Summary of the Invention

[0013] Problems to be solved by the invention

[0014] The present invention has been developed for the purpose of preventing the above-mentioned drawbacks. One of the objects of the present invention is to provide a battery assembly, an electric vehicle, and a power storage device including the battery assembly, which can protect an electronic circuit block having a voltage detection circuit from the influence of high-temperature and high-pressure exhaust gas and achieve high safety, and further efficiently dissipate heat from the electronic circuit block.

[0015] Solutions for solving the problems

[0016] A battery assembly according to an aspect of the present invention includes a battery stack formed by stacking a plurality of battery cells, a pair of end plates disposed at both ends in the stacking direction of the battery stack, a binding strip that connects the pair of end plates to fix the battery cells, and an electronic circuit block on which a voltage detection circuit for detecting the voltage of the battery cells is mounted, and the electronic circuit block is disposed on the surface of the end plate.

[0017] An electric vehicle according to an aspect of the present invention includes: the above-mentioned battery assembly; a driving motor that is supplied with power from the battery assembly; a vehicle body that mounts the battery assembly and the motor; and wheels that are driven by the motor to make the vehicle body travel.

[0018] A power storage device according to an aspect of the present invention includes the above-mentioned battery assembly and a power supply controller that controls charging and discharging with respect to the battery assembly. Using the power supply controller, it is possible to charge the battery cells with external power and perform control to charge the battery cells.

[0019] Effects of the invention

[0020] The above battery assembly can protect an electronic circuit block with a voltage detection circuit from the influence of exhaust gas at high temperature and high pressure, achieving high safety and efficiently dissipating heat from the electronic circuit block. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FIG. 1 is a perspective view of a battery assembly according to an embodiment of the present invention.

[0022] Figure 2 FIG. 2 Figure 1 is an exploded perspective view of the battery assembly shown in FIG. 1.

[0023] Figure 3 FIG. 3 is an exploded perspective view of the battery assembly shown in FIG. 1 as viewed from below. Figure 1 FIG. 4 is a cross-sectional view taken along line IV-IV of the battery assembly shown in FIG. 1.

[0024] Figure 4 FIG. 5 Figure 1 is a top view of the end portion of the battery assembly shown in FIG. 1.

[0025] Figure 5 FIG. 6 Figure 1 is a cross-sectional view taken along line VI-VI of the battery assembly shown in FIG. 1.

[0026] Figure 6 FIG. 7 Figure 5 is a circuit diagram showing an example of an electronic circuit block.

[0027] Figure 7 FIG. 8 is an enlarged top view showing another example of the connection structure between the end plate and the electronic circuit block.

[0028] Figure 8 FIG. 9 is a block diagram showing an example of mounting the battery assembly on a hybrid vehicle that travels using an engine and an electric motor.

[0029] Figure 9 FIG. 10 is a block diagram showing an example of mounting the battery assembly on an electric vehicle that travels only using an electric motor.

[0030] Figure 10 FIG. 11 is a block diagram showing an example of using the battery assembly in a power storage device.

[0031] Figure 11 FIG. 12 is an exploded perspective view of a conventional battery assembly.

[0032] Figure 12 DETAILED DESCRIPTION OF THE INVENTION DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Hereinafter, the present invention will be described in detail based on the accompanying drawings. In addition, in the following description, terms indicating specific directions and positions (for example, "upper", "lower", and other terms including these terms) are used as needed, but the purpose of using these terms is to facilitate understanding of the invention with reference to the drawings, and the scope of protection of the present invention is not limited to the meanings of these terms. In addition, parts with the same reference numerals shown in multiple drawings represent the same or equivalent parts or components.

[0034] Moreover, the embodiments shown below are embodiments that represent specific examples of the technical idea of the present invention, and the present invention is not limited to the following embodiments. In addition, regarding the dimensions, materials, shapes, relative arrangements, etc. of the constituent components described below, unless otherwise specifically stated, it is not intended to limit the scope of the present invention only thereto, but is intended to be illustrative. In addition, the content described in one embodiment or example can also be applied to other embodiments or examples. In addition, in order to make the description clear, the sizes, positional relationships, etc. of the components shown in the drawings are sometimes exaggerated.

[0035] The battery assembly according to the first embodiment of the present invention includes a battery stack formed by stacking a plurality of battery cells, a pair of end plates disposed at both ends in the stacking direction of the battery stack, a tightening bar connecting the pair of end plates, and an electronic circuit block in which a voltage detection circuit for detecting the voltage of the battery cell is installed, and the electronic circuit block is disposed on the surface of the end plate.

[0036] The above battery assembly has the following advantages: it can protect the circuit board from the high-temperature and high-pressure exhaust gas ejected from the exhaust valve of the battery cell, while miniaturizing the battery assembly and increasing the charge and discharge capacity per unit volume. Moreover, it can efficiently dissipate the heat energy of the electronic circuit block on which the voltage detection circuit is installed to the end plate and the outside, reducing the temperature rise of the electronic circuit block. In particular, the above structure has the following advantages: the electronic circuit block can be disposed on the surface of the end plate in a vertical posture, so that air can smoothly convect on the surface of the electronic circuit block to dissipate heat efficiently. In addition, in the electronic circuit block where the high-temperature and high-pressure exhaust gas is blocked by the end plate, even in the abnormal use state of the battery cell with the exhaust valve opened, it can be set to a normal operating state to ensure high safety. The characteristic of being able to efficiently dissipate the heat energy of the electronic circuit block also realizes the following advantages: it can miniaturize the electronic circuit block while reducing the temperature rise. It also realizes the following advantages: it also reduces the temperature rise of the electronic components installed on the electronic circuit block, ensuring the stable operation of the electronic components.

[0037] In the battery assembly according to the second embodiment of the present invention, a gas passage is disposed opposite to the terminal surface of the battery cell.

[0038] In the above battery assembly, there is no need to arrange the electronic circuit block for installing the voltage detection circuit on the terminal surface of the battery cell. Therefore, it has the following advantages: On the terminal surface of the battery cell, a gas passage that makes the gas flow path a large area is arranged, and high-temperature and high-pressure exhaust gas can be discharged more quickly. The following advantages are also achieved: For the gas passage that enables the exhaust gas to flow smoothly inside, leakage of the exhaust gas is also prevented, and disadvantages caused by the gas leaking to the outside of the passage are prevented, that is, combustion of the connector and lead caused by the leaked gas is prevented, and chain smoking and fire of the battery cell caused thereby are prevented, and relatively high safety can be ensured. Moreover, since the electronic circuit block is not arranged near the gas passage, the occurrence of a short-circuit failure of the electronic circuit block caused by foreign matters such as metal flakes contained in the exhaust gas can be suppressed.

[0039] In the battery assembly according to the third embodiment of the present invention, the electronic circuit block is fixed to the outer surface of the end plate in a thermally coupled state.

[0040] The above battery assembly has the following advantages: The heat energy of the electronic circuit block can be efficiently conducted to the end plate, and the temperature rise of the electronic circuit block is reduced. In particular, the end plate requires a strong structure for fixing a plurality of battery cells, so it is relatively heavy and has a large specific heat capacity, and the amount of heat energy generated by the electronic circuit block absorbed is large. Therefore, the heat energy of the electronic circuit block is efficiently absorbed and the temperature rise is reduced.

[0041] In the battery assembly according to the fourth embodiment of the present invention, the outer shape of the electronic circuit block is smaller than the outer shape of the end plate, and the electronic circuit block is arranged on the surface without protruding from the outer periphery of the end plate.

[0042] In the above battery assembly, the electronic circuit block is arranged on the end plate, and at the same time, the electronic circuit block does not protrude from the outer periphery of the end plate. Therefore, the electronic circuit block does not increase the outer shape of the battery assembly.

[0043] In the battery assembly according to the fifth embodiment of the present invention, the end plate is made of metal.

[0044] This battery assembly has the following advantages: The heat energy of the electronic circuit block can be dissipated more efficiently by using the metal end plate. The reason is that the metal end plate has excellent heat conduction characteristics and a large specific heat capacity, and can efficiently absorb and dissipate the heat energy of the electronic circuit block.

[0045] In the battery assembly according to the sixth embodiment of the present invention, the electronic circuit block is fixed to the end plate in an insulated state.

[0046] In the battery assembly according to the seventh embodiment of the present invention, the electronic circuit block includes an equalization circuit for battery cells.

[0047] The above battery assembly has the following advantages: The end plate efficiently dissipates heat from the heating components of the equalization circuit of the electronic circuit block, so that the battery cells can be equalized quickly by the equalization circuit. The reason is that by increasing the power consumption of the equalization circuit and discharging the battery cells with a large current, the voltage of the high-voltage battery cells can be quickly reduced. The equalization circuit eliminates the voltage imbalance by discharging the high-voltage battery cells, or equalizes by charging the low-voltage battery cells with the high-voltage battery cells. In the circuit for equalizing by discharging the high-voltage battery cells, the high-voltage battery cells are discharged using a discharge resistor. In the equalization circuit for charging the low-voltage battery cells with the high-voltage battery cells, power is supplied from the high-voltage battery cells to the low-voltage battery cells for equalization. In the circuit for equalizing by discharging the battery cells using a discharge resistor, the discharge resistor for discharging the battery cells and the semiconductor element for controlling the discharge current of the discharge resistor generate heat. For this circuit, as a structure for efficiently dissipating the heat energy of the discharge resistor and the semiconductor element, the discharge current of the discharge resistor and the semiconductor element can be increased to shorten the equalization time. If the discharge current is increased, the heat generation amount also becomes larger, so that efficient discharge can be achieved by increasing the discharge current. In addition, in the equalization circuit for charging the low-voltage battery cells with the high-voltage battery cells, the semiconductor element for controlling the current from the high-voltage battery cells to the low-voltage battery cells generates heat, so that the current of the semiconductor element can be increased to shorten the equalization time.

[0048] In the battery assembly according to the eighth embodiment of the present invention, the electronic circuit block includes a wireless communication circuit.

[0049] In the battery assembly according to the ninth embodiment of the present invention, the end plate integrally has a shielding convex portion that shields the outer peripheral edge of the electronic circuit block.

[0050] In the battery assembly according to the tenth embodiment of the present invention, a bottom plate for fixing the end plate is provided. The bottom plate has a bracket protruding from the outer side surface of the end plate, and the electronic circuit block is shaped such that it does not protrude outward from the top edge of the bracket in a plan view.

[0051] In the above battery assembly, the electronic circuit block is fixed to the end plate, and the outer shape in a plan view is not larger than that of the bottom plate. Therefore, the battery assembly has the following advantages: The electronic circuit block can be arranged at an ideal position while being miniaturized.

[0052] In the battery assembly according to the eleventh embodiment of the present invention, the lower part of the electronic circuit block is fixed to the bracket.

[0053] The above battery assembly has the following advantages: The electronic circuit block can be reliably fixed to the bottom plate while being miniaturized.

[0054] In the battery assembly according to the 12th embodiment of the present invention, the bracket has a fixing hole, and the electronic circuit block is arranged at a position different from the fixing hole in a top view.

[0055] The above battery assembly has the following advantages: The electronic circuit block can be fixed to the end plate, and at the same time, the bottom plate can be simply and reliably fixed to the using device.

[0056] In the battery assembly according to the 13th embodiment of the present invention, for the electronic circuit block, a part of the upper edge portion is locally fixed to the end plate, and the lower portion is fixed to the bracket.

[0057] In the above battery assembly, even if the battery cell expands and the end plate deforms, this deformation will not have an adverse effect on the electronic circuit block. In a battery assembly with multiple battery cells stacked, the expansion of the battery cells deforms the end plate. In a battery assembly with multiple battery cells stacked, when charging and discharging are repeated, the battery cells expand and the end plate deforms. The end plate fixes the tightening strips on both sides, so the expansion of the battery cells causes the center of the end plate to bulge and bend. If the electronic circuit block fixed to the end plate deforms together with the end plate, the strain caused by the deformation will have an adverse effect on the electronic circuit block. For example, in an electronic circuit block that fixes electronic components to a circuit board, the circuit board bends and drawbacks such as breakage of the conductive part occur. In the above battery assembly, a part of the upper edge portion of the electronic circuit block is locally fixed to the end plate, so even if the end plate bends, it will not deform together. In addition, for the electronic circuit block, the lower portion is fixed to the bracket of the bottom plate, so it is reliably fixed at the upper and lower parts. That is, the electronic circuit block is firmly fixed to the end plate and the bottom plate without being affected by the deformation of the end plate.

[0058] In the battery assembly according to the 14th embodiment of the present invention, the electronic circuit block is locally fixed to the end plate.

[0059] In the battery assembly according to the 15th embodiment of the present invention, the electronic circuit block is fixed to the surface of the end plate with a rubber-like elastic body interposed therebetween.

[0060] In the above battery assembly, the electronic circuit block is fixed to the end plate with a rubber-like elastic body interposed therebetween. Therefore, it is possible to prevent the adverse effects caused by the deformation of the end plate, and at the same time, the electronic circuit block is reliably fixed to the end plate. In addition, the electronic circuit block is closely attached to the end plate over a large area with a rubber-like elastic body interposed therebetween, and the electronic circuit block and the end plate are fixed in a preferable thermal coupling state, which can improve the heat dissipation characteristics of the electronic circuit block.

[0061] (Embodiment 1)

[0062] The battery module shown in the following embodiments is mainly most suitable as a power source for electric vehicles such as hybrid vehicles that run using both an engine and an electric motor, plug-in hybrid vehicles, electric vehicles that run only using an electric motor, and electric motorcycles that run using an electric motor. However, the battery module of the present invention is also suitable as a power source for a power storage device for applications other than electric vehicles that require high output.

[0063] Figures 1 to 6 The battery module shown includes a battery laminate 2 formed by laminating a plurality of battery cells 1 in the thickness direction, a pair of end plates 3 disposed at both ends in the lamination direction of the battery cells 1 of the battery laminate 2, a tightening strip 4 connected to the end plates 3 at both ends of the battery laminate 2, and an electronic circuit block 6 connected to the battery cells 1 of the battery laminate 2 via leads 19. Moreover, the illustrated battery module includes: a gas passage 5 that is connected to the exhaust valve 1a of each battery cell 1 and discharges the discharged gas ejected from the exhaust valve 1a to the outside; an upper surface cover 8 that is disposed above the battery laminate 2 and above the gas passage 5; and a bottom plate 9 that is disposed below the battery laminate 2 and fixes the end plates 3.

[0064] (Battery cell 1)

[0065] As Figure 2 shown, the battery cell 1 is a square secondary battery whose width is larger than its thickness, in other words, whose thickness is smaller than its width, and is laminated in the thickness direction to form the battery laminate 2. The battery cell 1 is a lithium-ion secondary battery. However, the battery cell can also be other rechargeable secondary batteries such as nickel-metal hydride batteries and nickel-cadmium batteries. In the battery cell 1, positive and negative electrode plates and an electrolyte are housed together in an externally mounted can with a sealed structure. For the externally mounted can, a metal plate such as aluminum or an aluminum alloy is press-formed into a square shape, and the opening is hermetically sealed with a sealing plate. For the sealing plate, positive and negative electrode terminals 11 are fixed using the same aluminum or aluminum alloy as the externally mounted can, and an exhaust valve is provided between the electrode terminals 11. In addition, at least one of the positive and negative electrode terminals 11 is in a state of being insulated from the sealing plate. In this battery cell 1, the sealing plate is used as the terminal surface 10 and positive and negative electrode terminals 11 are provided. Moreover, in the battery cell 1, the bottom surface and side surface of the externally mounted can are covered with an insulating film.

[0066] A plurality of battery cells 1 are laminated such that the thickness direction of each battery cell 1 becomes the lamination direction to form the battery laminate 2. In the battery cell, one outer peripheral surface of a quadrilateral is used as the terminal surface 10 provided with positive and negative electrode terminals 11, the terminal surfaces 10 are arranged in the same plane, and a plurality of battery cells 1 are laminated to form the battery laminate 2.

[0067] (Battery laminate 2)

[0068] As Figure 2As shown, in the battery laminate 2, an insulating spacer 12 is interposed between the stacked battery cells 1. The insulating spacer 12 in the figure is made of an insulating material such as resin into a thin plate shape or sheet shape. The illustrated insulating spacer 12 is set to a plate shape having a size substantially equal to the opposing surface of the battery cell 1, and the insulating spacer 12 is stacked between adjacent battery cells 1 to insulate the adjacent battery cells 1 from each other. In addition, as a spacer disposed between adjacent battery cells 1, a spacer having a shape in which a flow path for cooling gas is formed between the battery cell and the spacer can also be used.

[0069] In the battery laminate 2, a metal bus bar 14 is connected to the positive and negative electrode terminals 11 of adjacent battery cells 1, and a plurality of battery cells 1 are connected in series, in parallel, or in series and parallel using the bus bar 14. In the battery laminate 2, the output voltage and the charge-discharge capacity are set to a set value according to the number of stacked battery cells 1. In the battery laminate 2, the output voltage can be increased by the number of battery cells 1 connected in series, and the charge-discharge capacity can be increased by the number of battery cells 1. For the battery module, the output voltage and the capacity are set to a set value according to the number of battery cells 1 constituting the battery laminate 2 and their connection states in parallel and in series. Therefore, for the number and connection state of the battery cells 1, the optimal state is set in consideration of the use.

[0070] The bus bar 14 is provided with a connection portion (not shown) for connecting to the electrode terminal 11. The bus bar 14 is welded and connected to the electrode terminal 11 by irradiating a laser beam on the boundary connecting the connection portion and the electrode terminal 11. However, for the bus bar, it can also be connected to the electrode terminal by providing an external thread on the electrode terminal, providing a through hole through which the electrode terminal passes, and screwing a nut onto the external thread of the electrode terminal passing through the through hole, or by providing an internal threaded hole on the electrode terminal and screwing a set screw passing through the bus bar into the internal threaded hole. In the battery module, a resin insulating cover (not shown) can be provided on the upper surface of the battery laminate 2. For the insulating cover, an opening can be provided to expose the electrode terminal 11 from the opening, and on the upper surface side of the insulating cover, a bus bar 14 of a metal plate is connected to the electrode terminal 11 exposed from the opening of the insulating cover, and a plurality of battery cells 1 are connected in a predetermined arrangement.

[0071] (End face spacer 13)

[0072] In the battery laminate 2, in order to insulate from the metal end plates 3, the end plates 3 can be arranged with an end face spacer 13 interposed therebetween on both end faces. The end face spacer 13 is arranged between the battery laminate 2 and the end plates 3 to insulate the end plates 3 from the battery laminate 2. The end face spacer 13 is made of an insulating material such as resin into a thin plate shape or sheet shape. The end face spacer 13 is provided with a plate portion sized to cover the entire opposite faces of the battery cells 1, and this plate portion is laminated between the battery cells 1 arranged at both ends of the battery laminate 2 and the end plates 3.

[0073] (End plate 3)

[0074] The end plates 3 are located on both end faces in the stacking direction of the battery cells 1 of the battery laminate 2 and fix the battery laminate 2. The end plates 3 are metal plates, and are quadrilateral plates having an outer shape substantially equal to or slightly larger than that of the battery cells 1. The end plates 3 can be made of high-tensile steel into a strong structure. The end plates 3 can be configured as a single metal plate or a structure in which multiple metal plates are stacked, or can be configured as a laminate of a metal plate and plastic. The specific heat capacity of the end plate 3 composed of a single metal plate is relatively large, and can efficiently absorb the heat energy of the electronic circuit block 6. In addition, for an end plate in which multiple plates are stacked, at least the surface side for fixing the electronic circuit block is made of a metal plate. The purpose is to fix the electronic circuit block in a thermally coupled state and improve the heat dissipation characteristics. Moreover, the end plate can be configured as a laminated structure of an aluminum plate and a high-tensile steel plate. This end plate can also be configured as follows: the surface side is an aluminum plate for fixing the electronic circuit block, the aluminum plate and the high-tensile steel plate are stacked in a surface-contact state, and heat can be efficiently conducted from the aluminum plate to the high-tensile steel plate. However, the end plate does not necessarily have to be made of metal, and can also be made of a plastic with excellent strength such as engineering plastic.

[0075] (Tightening strip 4)

[0076] The tightening strip 4 extends along the stacking direction of the battery cells 1 and fixes both end portions to the end plates 3, and the battery laminate 2 is fixed by a pair of end plates 3. The tightening strip 4 is a metal plate having a predetermined vertical width and a predetermined thickness along the side surfaces of the battery laminate 2, and is arranged opposite to both side surfaces of the battery laminate 2. The tightening strip 4 presses the both end faces of the battery laminate 2 with a strong pressure to arrange the battery cells 1 that are to expand during charge and discharge at fixed positions. The metal plate of the tightening strip 4 is preferably made of high-tensile steel. The metal plate of the tightening strip 4 is formed into a predetermined shape by press forming.

[0077] For the tightening strip 4, as Figure 2 and Figure 3As shown in the exploded perspective view, in order to fix both ends to a pair of end plates 3, fixing portions 4A are provided at both ends in the stacking direction of the battery stack 2 by bending both end portions thereof along the outer side surfaces of the end plates 3. The tightening strip 4 fastens the pair of end plates 3 by screwing the fixing portion 4A to the end plates 3 or the like.

[0078] Moreover, for the tightening strip 4, as Figures 2 to 4 shown, the lower end portion is bent into an L shape to form a lower connecting piece 4B. The lower connecting piece 4B is stacked on the lower surface sides of both side portions of the bottom plate and connected to the bottom plate. Moreover, for the tightening strip 4, the upper end portion is bent to form a pressing piece 4C that presses the upper surface of the battery stack 2. The pressing pieces 4C are separated for each battery cell 1 so as to be able to individually press the upper surface of the battery cell 1 of the battery stack 2. Thus, each pressing piece 4C can press the battery cell 1 toward the bottom plate 9 independently of the adjacent pressing pieces 4C. In this way, it is possible to prevent each battery cell 1 from floating up from the bottom plate 9 and maintain each battery cell 1 in the height direction, and even if vibrations, shocks, etc. are applied to the battery stack 2, it is possible to maintain that each battery cell 1 is not displaced in the vertical direction. In this way, the tightening strip 4 covers and holds the corner portions of the upper and lower surfaces of the battery stack 2 at both left and right side portions of the battery stack 2.

[0079] In addition, the shape of the tightening strip 4 and the fastening structure with the end plate 3 can appropriately utilize known structures. For example, it can be configured such that the both end portions of the tightening strip are not bent into an L shape but are formed into flat plate shapes and are screwed to the side surface of the end plate. Or, it can be configured as follows: the portion of the tightening strip facing the side surface of the end plate is provided with a snap-fit structure in which the steps are engaged, and in a state where the tightening strip is snapped to the side surface of the end plate by using the snap structure, further screwing is performed.

[0080] Alternatively, an insulating sheet can be interposed between the tightening strip 4 and the battery stack 2. The insulating sheet is made of a material having insulating properties such as resin or the like, and insulates the metal tightening strip 4 from the battery cell 1.

[0081] (Bottom plate 9)

[0082] As Figure 4 and Figure 6 shown, the bottom plate 9 is disposed on the bottom surfaces of the battery stack 2 and the end plates 3. The bottom plate 9 is for fixing the end plates 3, and more preferably, the lower end portion of the tightening strip 4 is also fixed thereto. The end plates 3 and the tightening strip 4 are fixed to the bottom plate 9 by fixing screws 15 and 16. The fixing screw 15 for fixing the end plate 3 penetrates the end plate 3 in the vertical direction and fixes the end plate 3 to the bottom plate 9. In addition, the fixing screw 16 for fixing the tightening strip 4 also penetrates the lower connecting piece 4B which is the lower end portion of the tightening strip 4 and is fixed to the bottom plate 9.

[0083] The bottom plate 9 is provided with brackets 17 at both ends for fixing the battery module 100 to a mounting device such as a vehicle. As Figure 5 and Figure 6 shown, the brackets 17 are provided to protrude outward from the end plate 3. The brackets 17 are provided with fixing holes 17A through which a set screw (not shown) passes, and are fixed to the chassis of a vehicle or the like as a mounting device by means of the set screw. The set screw passes through the brackets 17 and is screwed into the chassis of the vehicle or the like to fix the battery module 100 to a fixed position.

[0084] In the battery laminate 2, each battery cell 1 is brought into contact with the bottom plate 9 and arranged in a thermally coupled state with the bottom plate 9. In the battery cell 1 thermally coupled to the bottom plate 9, heat energy is dissipated to the bottom plate 9. Moreover, the bottom plate 9 can also be forcibly cooled to more efficiently dissipate the heat energy of the battery cell 1. Although not shown, a refrigerant or a coolant can be circulated inside the bottom plate 9 being forcibly cooled for forced cooling. In addition, heat sinks can also be provided on the lower surface of the bottom plate for forced cooling. Moreover, a cooling plate can also be laminated on the lower surface of the bottom plate in a surface contact state, and the cooling plate is used for forced cooling. For the cooling plate, a refrigerant or a coolant can be circulated inside for forced cooling.

[0085] (Gas passage 5)

[0086] As Figure 4 shown, a gas passage 5 is arranged at a position opposite to the upper surface of the battery cell 1, i.e., the terminal surface 10 of the battery cell 1. The gas passage 5 is a cylindrical shape with an internal volume for smoothly discharging the ejected matter discharged from the opening of the exhaust valve 1a, and is open at the lower surface and connected to the opening of the exhaust valve 1a of each battery cell 1. The gas passage 5 is closely attached to the upper surface of the battery laminate 2 on the upper surface of the battery laminate 2 in such a manner that no gap is formed between the gas passage 5 and the terminal surface 10 of the battery cell 1 to discharge the exhaust gas discharged from the exhaust valve 1a to the outside, and the opening 5a open at the lower surface is connected to the exhaust valve 1a of each battery cell 1. The gas passage 5 can also be arranged with a gasket, a sealing material, etc. between the gas passage 5 and the terminal surface 10 to prevent the exhaust gas from leaking.

[0087] Moreover, although not shown, the gas passage can also be composed of a collecting passage and a branch passage. The collecting passage is arranged on the upper surface of the battery laminate in a posture extending along the stacking direction of the battery cells, and the branch passage is connected to the collecting passage and has its top end connected to the exhaust valve. In this gas passage, the collecting passage can be arranged separately from the terminal surface, and the top end of the branch passage can be connected to the opening of the exhaust valve.

[0088] (Electronic circuit block 6)

[0089] As Figure 7As shown, the electronic circuit block 6 includes a voltage detection circuit 22, which is connected to each battery cell 1 via leads and detects the voltage of the battery cell 1. In the electronic circuit block 6, the electronic components that implement the voltage detection circuit 22 are mounted on a circuit board 20 (see Figure 5 and Figure 6 ). However, the electronic circuit block 6 can also be configured as follows: all the electronic circuits including the voltage detection circuit 22 are made into an integrated circuit, and the integrated circuit is embedded in a package of an insulating material. As shown in Figure 5 and Figure 6 , the electronic circuit block 6 can be configured as a block with a heat sink 21 arranged on the surface of a metal plate. The heat sink 21 is thermally coupled to the heat-generating components built in the electronic circuit block 6, such as the discharge resistors of the equalization circuit, semiconductor elements such as FETs that control current, etc., and dissipates the thermal energy of these heat-generating components to the outside. The electronic circuit block 6 is made into a plate shape by mounting electronic components on the circuit board 20, or is made into a plate shape by embedding the integrated circuit in a package.

[0090] The electronic circuit block 6 having the voltage detection circuit 22 detects the voltage of the battery cell 1 whose voltage changes during charge and discharge, and prevents overcharging and over-discharging of each battery cell 1. The battery assembly may also include a control circuit 30 that controls the charge and discharge current of the battery stack 2. The control circuit 30 controls the charge and discharge current to prevent overcharging and over-discharging of the battery cell 1. The voltage detection circuit 22 transmits the voltage data of the battery cell 1 to the control circuit 30.

[0091] The voltage detection circuit 22 preferably detects the voltages of all the battery cells 1. However, it is not necessary for the voltage detection circuit 22 to detect the voltages of all the battery cells 1. For example, the battery cells 1 constituting the battery stack 2 can be divided into a plurality of battery units, and the voltages of the respective battery units can be detected. In a battery unit in which a plurality of battery cells 1 are connected in parallel, the voltage of the battery unit can be detected to detect the voltages of all the battery cells. In a battery unit in which a plurality of battery cells are connected in series, the voltage of the battery unit is detected to detect the total voltage of the battery cells connected in series. The battery unit in which a plurality of battery cells are connected in series is composed of 2 to 5 battery cells. In this battery unit, the voltage of the battery unit is detected to detect the total voltage of 2 to 5 battery cells 1, so the voltage of the battery cell becomes 1 / 2 to 1 / 5 of the detected total voltage. The voltage of the battery cell 1 changes according to the remaining capacity. The voltage of the battery cell 1 becomes higher than a preset maximum voltage during overcharging and lower than the minimum voltage during over-discharging. The electrical characteristics of the battery cell 1 deteriorate during overcharging or over-discharging, and the safety also decreases. The voltage detection circuit 22 detects the voltage of the battery cell 1 and transmits it to the control circuit, and the control circuit controls the charge and discharge current so that the voltage of the battery cell 1 is within the set range.

[0092] In a battery module, as charging and discharging are repeated, the remaining capacities of the individual battery cells 1 become unbalanced. The battery cells 1 connected in series are charged and discharged with the same current. Although they are charged and discharged with the same current, the electrical characteristics of the individual battery cells 1 are not exactly the same. Therefore, also in a battery module in which a plurality of battery cells 1 are connected in series, the voltages of the individual battery cells 1 become unbalanced. The imbalance of the battery cells 1 causes overcharging or over-discharging of a specific battery cell 1. In the battery module, since all the battery cells 1 are charged and discharged simultaneously, the imbalance of the battery cells 1 causes overcharging or over-discharging of a specific battery cell 1. The overcharging and over-discharging of the battery cell 1 cause deterioration by reducing the electrical characteristics of the battery cell 1, and also reduce the safety of the battery module. The equalization circuit 23 eliminates the imbalance of the voltages of the battery cells 1.

[0093] The electronic circuit block 6 is also provided with an equalization circuit 23 for equalizing the voltages of the battery cells 1. The equalization circuit 23 eliminates the imbalance by equalizing the voltages of the battery cells 1. An example of the circuit diagram of the equalization circuit 23 is shown in Figure 7 . In the equalization circuit 23 shown in this figure, a discharge resistor 25 is used to discharge the battery cell 1 with a higher voltage to eliminate the imbalance. However, the equalization circuit is not limited to a circuit that discharges a battery using a discharge resistor. For example, for the equalization circuit, it is also possible to discharge a battery cell with a higher voltage to a capacitor, a storage battery, or other electrical storage device to store electricity in the electrical storage device, and then discharge the charge of the electrical storage device to a battery cell with a lower voltage to eliminate the voltage difference between the battery cells. In addition, for the equalization circuit, it is also possible to use a DC / DC converter to convert the voltage of a battery cell with a higher voltage, and while controlling the current, charge a battery cell with a lower voltage to equalize the voltages.

[0094] In Figure 7 the equalization circuit 23, a discharge circuit 24 in which a switching element 26 is connected in series with the discharge resistor 25 is provided, a control circuit 27 and a voltage detection circuit 22 are connected, the control circuit 27 detects each cell voltage and controls the switching element 26 to be turned on / off, and the voltage detection circuit 22 detects the cell voltage of each battery cell 1. The discharge circuit 24 of the discharge resistor 25 and the switching element 26 is connected in parallel with each battery cell 1. For this equalization circuit 23, when the cell voltage of the battery cell 1 becomes high, the switching element 26 is switched to on by the control circuit 27, and the battery cell 1 is discharged by the discharge resistor 25 to reduce the voltage of the battery cell 1 and equalize it.

[0095] Moreover, the equalization circuit 23 is driven by receiving power supply from the battery stack 2. The equalization circuit 23 in the figure operates using the output voltage (Vcc) of the power supply circuit 28 that receives power supply from the battery stack 2. The voltage of the battery stack 2 can be stepped down by a DC / DC converter as the power supply circuit 28 and supplied to the equalization circuit 23, for example. According to this circuit configuration, even if the voltage of the battery stack 2 is high, it can be supplied to the equalization circuit 23 as an optimal voltage.

[0096] The regulation circuit 27 compares the individual voltages of the respective battery cells 1 and controls the switching element 26 to equalize the individual voltages of all the battery cells 1. The regulation circuit 27 discharges by switching the switching element 26 of the discharge circuit 24 connected to the battery cell 1 with too high a voltage to on. The voltage of the battery cell 1 decreases as it discharges. When the voltage of the battery cell 1 decreases to balance with other battery cells 1, the switching element 26 is switched from on to off. When the switching element 26 is off, the discharge of the battery cell 1 stops. In this way, the regulation circuit 27 balances the individual voltages of all the battery cells 1 by discharging the battery cell 1 with a higher individual voltage.

[0097] The above equalization circuit 23 equalizes the voltages of all the battery cells 1. However, in a battery module, all the battery cells can also be divided into a plurality of battery units. After equalizing the voltages of the battery cells constituting the battery unit using an individual equalization circuit, the voltages of the entire battery units are equalized using a unit equalization circuit. In the unit equalization circuit, the unit voltages of the respective battery units are detected, and the battery unit with a higher unit voltage is discharged to equalize the voltages of the respective battery units.

[0098] The electronic circuit block 6 is fixed to the end plate 3 and dissipates heat to the end plate 3. The electronic circuit block 6 includes semiconductor elements such as FETs that control current, and heating elements such as discharge resistors. The electronic circuit block 6 can dissipate the thermal energy of the heating elements to the end plate 3 to reduce the temperature rise. The temperature rise of the electronic circuit block 6 has an adverse effect on the built-in heating elements and the like. In particular, for the equalization circuit 23, the battery cell 1 is discharged using the discharge resistor 25 to reduce the voltage, but the discharge resistor 25 generates heat due to the Joule heat of the discharge current. The discharge resistor 25 can increase the current and rapidly reduce the voltage of the battery cell 1 in a short time. However, the Joule heat that heats the discharge resistor 25 increases in proportion to the square of the discharge current. Therefore, the thermal energy generated by the equalization circuit 23 that can rapidly reduce the voltage of the battery cell 1 and shorten the equalization time becomes large. The equalization circuit 23 equalizes the battery cell 1 when the battery cell 1 is not being charged or discharged, so further shortening of the equalization time is required. Shortening of the equalization time can be achieved by increasing the current of the discharge resistor 25. Therefore, how to efficiently dissipate the thermal energy of the discharge resistor 25 becomes an important factor in determining the equalization time.

[0099] The temperature rise caused by the heat energy generated by the heat-generating component leads to the failure of the component. Therefore, in order to avoid abnormal temperature rise of the heat-generating component, designs such as increasing the overall or reducing the heat generation per unit time of the discharge resistance are carried out. If the electronic circuit block 6 is miniaturized to be able to be arranged in a narrow space, the heat dissipation area is reduced, the heat energy dissipated is reduced, and the temperature rise becomes larger. Therefore, like the conventional battery module, the heat dissipation area of the electronic circuit block miniaturized to be able to be arranged in the tiny space of the gas passage and the bus bar becomes smaller, so it is necessary to reduce the heat energy dissipated. Thus, the electronic circuit block arranged in a narrow space needs to reduce the heat energy dissipated, and the time for equalizing the battery cells becomes longer. A battery module in which a plurality of battery cells are stacked is used for a battery module for driving a motor for a large-capacity application such as a vehicle, a power supply of a power storage device, etc. Therefore, the capacity of the battery cell is also quite large. For a large-capacity battery module, as the capacity of the battery cell expands, the imbalance in capacity caused by the imbalance in battery cell voltage relatively expands. Thus, such a battery module tries to shorten the equalization time of the battery cells and equalize them quickly, so the discharge current can be increased. However, since the increase in the discharge resistance causes an increase in the heat energy dissipated, an increase in the heat dissipation area is required. Thus, the electronic circuit block is required to be miniaturized in order to be arranged in a narrow space, and in order to shorten the equalization time by discharging with a large current, it is necessary to increase the heat dissipation area and become larger. Therefore, in the electronic circuit block, miniaturization and shortening of the equalization time are opposite characteristics, and the two characteristics cannot be satisfied. There are opposite problems such as miniaturization required for arranging in a limited space and enlargement required for having a high discharge capacity.

[0100] In a battery module in which the electronic circuit block 6 is fixed to the end plate 3 in a thermally coupled state and the end plate 3 is used for heat dissipation of the electronic circuit block 6, the heat energy dissipated by the electronic circuit block 6 can be efficiently dissipated by the end plate 3. In particular, the specific heat capacity of the end plate 3 is extremely large, and the temperature rise with respect to the absorbed heat energy is small, and the equalization time of the battery cell 1 can be shortened. Moreover, the surface area of the end plate 3 is also large, and the heat energy dissipated from the surface is also large, which also results in a smaller temperature rise. Also, in the structure in which the end plate 3 is fixed to the bottom plate 9, the heat energy is conducted from the end plate 3 to the bottom plate 9 and the temperature rise becomes further smaller. In addition, in the structure in which the bottom plate 9 is forcibly cooled or a cooling plate is stacked on the bottom plate 9, the end plate 3 is forcibly cooled by the bottom plate 9 and the temperature rise becomes further smaller, the cooling effect of the electronic circuit block 6 is further increased, and the temperature rise of the electronic circuit block 6 becomes smaller to an ideal state.

[0101] In Figure 5 and Figure 6In the battery assembly 100, the electronic circuit block 6 is fixed to the outer surface of the end plate 3. This battery assembly 100 has the following advantages: It can conduct and dissipate the heat generated by the electronic circuit block 6 to the fixed end plate 3, and can also dissipate heat from the exposed surface to the external air for more efficient heat dissipation. For the electronic circuit block 6 fixed to the surface of the end plate 3, its outer shape is smaller than that of the end plate 3 and does not protrude from the outer peripheral edge of the end plate 3. In this battery assembly 100, the electronic circuit block 6 is arranged on the end plate 3, and at the same time, the electronic circuit block 6 does not increase the outer shape of the battery assembly 100, enabling miniaturization while efficiently dissipating heat from the electronic circuit block 6.

[0102] Moreover, in Figure 5 the battery assembly 100, the thickness of the electronic circuit block 6 is set to a size that does not protrude outward from the top edge of the bracket 17 of the bottom plate 9 in a top view. In this battery assembly 100, the electronic circuit block 6 is fixed to the end plate 3, and at the same time, the outer shape in a top view is not larger than that of the bottom plate 9, enabling the electronic circuit block 6 to be arranged at an ideal position while miniaturizing the whole.

[0103] The end plate 3 is strongly pressed from the inside by the battery cell 1 that exhibits the physical property of expanding during charge and discharge. The end plate 3 that presses on the battery stack 2 and has its two side edges fixed by the tightening strip 4 bends under the pressure of the battery stack 2. If the electronic circuit block 6 is deformed due to the bent end plate 3, it will have an adverse effect on the components of the electronic circuit block 6. For example, in the electronic circuit block 6 where electronic components are fixed to a circuit board, the circuit board bends and drawbacks such as damage to the conductive part occur. For Figure 6 the electronic circuit block 6, a part of the upper edge part, preferably the central part, is locally fixed to the end plate 3, and the lower part is fixed to the bracket 17. In this battery assembly 100, even if the battery cell 1 expands and the end plate 3 is deformed, this deformation will not have an adverse effect on the electronic circuit block 6. In the above battery assembly 100, a part of the upper edge part of the electronic circuit block 6 is locally fixed to the end plate 3, so even if the end plate 3 bends, it will not be deformed together. In addition, for the electronic circuit block 6, the lower part is fixed to the bracket 17 of the bottom plate 9, so it is reliably fixed at the upper and lower parts. That is, the electronic circuit block 6 is firmly fixed to the end plate 3 and the bottom plate 9 without being affected adversely by the deformation of the end plate 3.

[0104] The battery assembly 100 that fixes the electronic circuit block 6 to the bracket 17 of the bottom plate 9 has the following advantages: By arranging the electronic circuit block 6 at a position different from the fixing hole 17A in a top view, the electronic circuit block 6 can be fixed to the end plate 3 while simply and reliably fixing the bottom plate 9 to a usage device such as the vehicle chassis. In Figure 5 the battery assembly 100, fixing holes 17A are provided at both side parts of the bracket 17, and the horizontal width is set to be able to be arranged inside the fixing holes 17A of the bracket 17.

[0105] The electronic circuit block 6 is preferably fixed to the end plate 3 in an insulated manner. The electronic circuit block 6 is fixed by disposing an insulating sheet 18 between it and the end plate 3. The insulating sheet 18, being an elastic sheet made of a rubber-like elastomer, can always keep the bent end plate 3 and the electronic circuit block 6 in a thermally coupled state. For the electronic circuit block 6 fixed to the end plate 3 in an insulated manner, it is configured to expose a metal radiator 21 or the like on the surface for efficient heat dissipation, and at the same time can improve the insulation characteristics with respect to the battery laminate 2 disposed inside the end plate 3 to enhance reliability. For the battery assembly 100 having end plates 3 disposed on both end faces of the battery laminate 2, by insulating the end plate 3 from the ground wire, electric shock and leakage can be prevented. The end plate 3 insulated from the ground wire has a high-voltage battery laminate 2 disposed inside. For the end plate 3 insulated from the battery laminate 2, the leakage resistance between the end plate 3 and the battery laminate 2 is kept high, but sometimes the leakage resistance decreases due to various reasons. For example, condensed water between the end plate 3 and the battery laminate 2 becomes a cause for reducing the leakage resistance. For the electronic circuit block 6 disposed in an insulated manner with respect to the end plate 3, even if the contact resistance between the end plate 3 and the battery laminate 2 decreases, it is insulated from the end plate 3 to prevent drawbacks such as leakage and electric shock and ensure high safety and reliability. However, since the end plate is insulated from the battery laminate, the end plate can also be connected to the ground wire.

[0106] The above battery assembly 100 has the following advantages: It can efficiently dissipate heat from the heating components of the equalization circuit 23 of the electronic circuit block 6 by using the end plate 3, so that the battery cells 1 can be equalized quickly by the equalization circuit 23. The reason is that by increasing the power consumption of the equalization circuit 23 and discharging the battery cells 1 with a large current, the voltage of the high-voltage battery cells 1 can be quickly reduced. The equalization circuit 23 eliminates the voltage imbalance by discharging the high-voltage battery cells 1, or equalizes by charging the low-voltage battery cells 1 with the high-voltage battery cells 1. In the circuit for equalization by discharging the high-voltage battery cells 1, the high-voltage battery cells 1 are discharged by the discharge resistor 25. In the equalization circuit 23 for charging the low-voltage battery cells 1 with the high-voltage battery cells 1, power is supplied from the high-voltage battery cells 1 to the low-voltage battery cells 1 for equalization. In the circuit for equalizing by discharging the battery cells 1 with the discharge resistor 25, the discharge resistor 25 for discharging the battery cells 1 and the switching element 26, i.e., the semiconductor element, for controlling the discharge current of the discharge resistor 25 generate heat. For this circuit, as a structure for efficiently dissipating the heat energy of the discharge resistor 25 and the semiconductor element, the discharge current of the discharge resistor 25 and the semiconductor element can be increased to shorten the equalization time. If the discharge current is increased, the heat generation amount also becomes larger, so that the discharge can be efficiently performed and the discharge current can be increased. In addition, in the equalization circuit for charging the low-voltage battery cells with the high-voltage battery cells, the semiconductor element for controlling the current flowing from the high-voltage battery cells to the low-voltage battery cells generates heat, so that the current of this semiconductor element can be increased to shorten the equalization time.

[0107] In the electronic circuit block 6 fixed to the end plate 3, as shown by the dotted line in Figure 7 , a wireless communication circuit 31 is provided. Information such as the battery voltage detected by the voltage detection circuit 22 can be wirelessly transmitted to the central control circuit 30 by using this wireless communication circuit 31. The electronic circuit block 6 does not need to be connected to the central control circuit 30 by leads and has the advantage of being able to be simply wired. In particular, in the battery assembly mounted on a vehicle, the electronic circuit block 6 can wirelessly transmit information to the central control circuit 30 that controls the driving motor of the vehicle. In the battery assembly with this structure, the unique complex wiring harness of the vehicle can be simplified, and drawbacks such as inevitable poor contact for the wiring harness can be prevented, and high reliability can be achieved in the long term.

[0108] The electronic circuit block 6 equipped with the wireless communication circuit 31 requires the characteristic of eliminating transmission errors caused by external noise. The metal end plate 3 can shield the surface of the electronic circuit block 6 to reduce the influence of external noise. In particular, as shown in Figure 8As shown, in the end plate 3 integrally provided with the shielding convex portion 32 that shields the outer peripheral edge of the electronic circuit block 6, the wireless communication circuit 31 can wirelessly transmit information stably and accurately. Moreover, by connecting the end plate to the ground wire, the shielding effect can be improved to further reduce the influence of external noise.

[0109] The above battery assembly can be used as a vehicle power source for supplying power to the motor that drives the electric vehicle. It can be used in electric vehicles such as hybrid vehicles, plug-in hybrid vehicles that use both an engine and a motor to drive, or electric vehicles that only use a motor to drive, and can be used as the power source for these vehicles. In addition, in order to obtain the power to drive the vehicle, a large-capacity and high-output battery assembly formed by connecting a plurality of the above battery assemblies in series and parallel and adding necessary control circuits can also be constructed and mounted.

[0110] (Battery assembly for hybrid vehicle)

[0111] Figure 9 An example of mounting a battery assembly on a hybrid vehicle that uses both an engine and a motor to drive is shown. The vehicle HV equipped with the battery assembly shown in this figure includes a vehicle body 91, an engine 96 that drives the vehicle body 91, a driving motor 93, wheels 97 driven by the engine 96 and the driving motor 93, a battery assembly 100 that supplies power to the motor 93, and a generator 94 that charges the battery of the battery assembly 100. The battery assembly 100 is connected to the motor 93 and the generator 94 via a DC / AC inverter 95. The vehicle HV travels using both the motor 93 and the engine 96 while charging and discharging the battery of the battery assembly 100. The motor 93 is driven to make the vehicle travel in regions where the engine efficiency is poor, such as during acceleration and low-speed driving. The motor 93 is driven by the power supplied from the battery assembly 100. The generator 94 is driven by the engine 96 or by regenerative braking when braking is applied to the vehicle, and charges the battery of the battery assembly 100. In addition, as shown in the figure, the vehicle HV may also be provided with a charging plug 98 for charging the battery assembly 100. By connecting the charging plug 98 to an external power source, the battery assembly 100 can be charged.

[0112] (Battery assembly for electric vehicle)

[0113] In addition, Figure 10An example of a battery pack mounted on an electric vehicle that runs only on an electric motor is shown. The vehicle EV with the mounted battery pack shown in the figure includes a vehicle body 91, a driving electric motor 93 that drives the vehicle body 91, wheels 97 driven by the electric motor 93, a battery pack 100 that supplies power to the electric motor 93, and a generator 94 that charges the battery of the battery pack 100. The battery pack 100 is connected to the electric motor 93 and the generator 94 via a DC / AC inverter 95. The electric motor 93 is driven by the power supplied from the battery pack 100. The generator 94 is driven by the energy during regenerative braking of the vehicle EV and charges the battery of the battery pack 100. In addition, the vehicle EV is equipped with a charging plug 98, and the battery pack 100 can be charged by connecting the charging plug 98 to an external power source.

[0114] (Battery pack for energy storage device)

[0115] Moreover, the present invention does not specifically limit the use of the battery pack to the power source of the electric motor for driving the vehicle. The battery pack of the embodiment can also be used as the power source of an energy storage device that charges and stores electricity using the power generated by solar power generation, wind power generation, etc. Figure 11 An energy storage device that charges and stores the battery of the battery pack 100 using a solar cell 82 is shown.

[0116] Figure 11 The energy storage device shown charges the battery of the battery pack 100 using the power generated by solar cells 82 arranged on the ridges, roofs, etc. of buildings 81 such as houses and factories. In this energy storage device, after charging the battery of the battery pack 100 using the solar cell 82 as a charging power source via a charging circuit 83, power is supplied to a load 86 via a DC / AC inverter 85. Therefore, this energy storage device has a charging mode and a discharging mode. In the energy storage device shown in the figure, the DC / AC inverter 85 and the charging circuit 83 are respectively connected to the battery pack 100 via a discharging switch 87 and a charging switch 84. The on / off of the discharging switch 87 and the charging switch 84 is switched by a power supply controller 88 of the energy storage device. In the charging mode, the power supply controller 88 switches the charging switch 84 to on and the discharging switch 87 to off, allowing charging from the charging circuit 83 to the battery pack 100. In addition, when charging is completed and the full charge state is reached, or in a state with a capacity above the charging predetermined value, the power supply controller 88 disconnects the charging switch 84 and turns on the discharging switch 87 to switch to the discharging mode, allowing discharging from the battery pack 100 to the load 86. In addition, the charging switch 84 can be turned on and the discharging switch 87 can be turned on as needed to supply power to the load 86 and charge the battery pack 100 simultaneously.

[0117] Moreover, although not shown, the battery module can also be used as a power source for a power storage device that charges and stores electricity using late-night power at night. The battery module charged by late-night power can be charged using late-night power, which is the surplus power of the power plant, and outputs power during the day when the power load is large, limiting the peak power during the day to a smaller value. Moreover, the battery module can also be used as a power source that charges using both the output of the solar cell and late-night power. The battery module effectively utilizes both the power generated by the solar cell and late-night power, and can efficiently store electricity while taking into account the weather and power consumption.

[0118] The power storage device as described above can be suitably used for applications such as a backup battery module that can be mounted on a rack of a computer server, a backup battery module for a wireless base station such as a mobile phone, a power storage power source for home or factory use, a power source for street lights, etc., a power storage device combined with a solar cell, a backup power source for a signal light, a traffic display for roads, etc.

[0119] Industrial applicability

[0120] The battery module of the present invention can be suitably used as a battery module for a plug-in hybrid electric vehicle, a hybrid electric vehicle, an electric vehicle, etc. that can switch between an EV driving mode and an HEV driving mode. In addition, it can also be suitably used for applications such as a backup battery module that can be mounted on a rack of a computer server, a backup battery module for a wireless base station such as a mobile phone, a power storage power source for home or factory use, a power source for street lights, etc., a power storage device combined with a solar cell, a backup power source for a signal light, etc.

[0121] Explanation of reference numerals

[0122] 100. Battery assembly; 1. Battery cell; 1a. Exhaust valve; 2. Battery laminate; 3. End plate; 4. Tightening strip; 4A. Fixing part; 4B. Lower side bending piece; 4C. Pressing piece; 5. Gas passage; 5a. Opening; 6. Electronic circuit block; 8. Upper surface cover; 9. Bottom plate; 10. Terminal surface; 11. Electrode terminal; 12. Insulating spacer; 13. End face spacer; 14. Bus bar; 15. Fixing screw; 16. Fixing screw; 17. Bracket; 17A. Fixing hole; 18. Insulating sheet; 19. Lead wire; 20. Circuit board; 21. Heat sink; 22. Voltage detection circuit; 23. Equalization circuit; 24. Discharge circuit; 25. Discharge resistor; 26. Switch element; 27. Regulation circuit; 28. Power supply circuit; 30. Control circuit; 31. Wireless communication circuit; 32. Shielding projection; 81. Building; 82. Solar cell; 83. Charging circuit; 84. Charging switch; 85. DC / AC inverter; 86. Load; 87. Discharge switch; 88. Power supply controller; 91. Vehicle body; 93. Motor; 94. Generator; 95. DC / AC inverter; 96. Engine; 97. Wheel; 98. Charging plug; 900. Battery assembly; 901. Battery cell; 901a. Exhaust valve; 902. Battery laminate; 903. End plate; 904. Tightening strip; 905. Gas passage; 906. Circuit board; 910. Terminal surface; 911. Electrode terminal; 914. Bus bar; HV, EV, Vehicle.

Claims

1. A battery assembly, characterized in that, the battery assembly includes a battery stack formed by stacking a plurality of battery cells, a pair of end plates disposed at both ends in the stacking direction of the battery stack, a tightening strip connecting the pair of end plates, and an electronic circuit block in which a voltage detection circuit for detecting the voltage of the battery cells is installed, the electronic circuit block is disposed on the surface of the end plate, the electronic circuit block is fixed to the outer surface of the end plate in a thermally coupled state, the electronic circuit block includes a balancing circuit for the battery cells, the electronic circuit block is a block of a metal plate on which a heat sink is disposed on the surface on the end plate side, the electronic circuit block includes a discharge resistor, the heat sink is thermally coupled to the discharge resistor, the end plate is made of metal, the electronic circuit block includes a wireless communication circuit, the end plate integrally has a shielding convex portion that shields the outer peripheral edge of the electronic circuit block.

2. The battery assembly according to claim 1, characterized in that, for the battery assembly, a gas passage is disposed opposite to the terminal surface of the battery cell.

3. The battery assembly according to claim 1 or 2, characterized in that, the outer shape of the electronic circuit block is smaller than the outer shape of the end plate, the electronic circuit block is disposed on the surface without protruding from the outer peripheral edge of the end plate.

4. The battery assembly according to claim 1, characterized in that, the electronic circuit block is fixed to the end plate in an insulating state.

5. The battery assembly according to claim 1 or 2, characterized in that, the battery assembly includes a bottom plate for fixing the end plate, the bottom plate has a bracket protruding from the outer surface of the end plate, the electronic circuit block has a shape that does not protrude outward from the top edge of the bracket in a top view.

6. The battery assembly according to claim 5, characterized in that, the lower part of the electronic circuit block is fixed to the bracket.

7. The battery assembly according to claim 6, characterized in that, the bracket has a fixing hole, the electronic circuit block is disposed at a position different from the fixing hole in a top view.

8. The battery assembly according to claim 6 or 7, characterized in that, for the electronic circuit block, a part of the upper edge portion is locally fixed to the end plate, the lower part is fixed to the bracket.

9. The battery assembly according to claim 1 or 2, characterized in that, the electronic circuit block is locally fixed to the end plate.

10. The battery assembly according to claim 1 or 2, characterized in that, the electronic circuit block is fixed to the surface of the end plate with a rubber-like elastic body interposed therebetween.

11. The battery assembly according to claim 1, characterized in that, the electronic circuit block is a block in which all the electronic circuits including the voltage detection circuit are integrated circuits, and the integrated circuits are embedded in an insulating material package.

12. The battery assembly according to claim 11, characterized in that, the electronic circuit block is formed into a plate shape by embedding the integrated circuit in the package.

13. An electric vehicle, comprising the battery assembly according to any one of claims 1 to 12, characterized in that, the electric vehicle includes: the battery assembly; A traveling electric motor that is supplied with power from the battery assembly; A vehicle body that mounts the battery assembly and the electric motor; and Wheels that are driven by the electric motor to make the vehicle body travel.

14. A power storage device comprising the battery assembly according to any one of claims 1 to 12, characterized in that The power storage device includes: The battery assembly; and A power supply controller that controls charging and discharging with respect to the battery assembly, Using the power supply controller, it is possible to charge the battery cell with external power and control to charge the battery cell.

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