Battery pack

Abstract

To provide a battery pack 40 capable of efficiently releasing heat from a battery cell 510 to the outside.SOLUTION: A battery pack 40 mounted on a hybrid system 10 includes a battery module 50 that supplies power to a motor generator 2, a control circuit that controls the battery module 50, a housing 400 that accommodates the battery module 50 and the control circuit, and an insulating heat conductive member 600 that is provided between the battery module 50 and the housing 400.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a battery pack installed in a hybrid system. [Background technology]

[0002] Patent Document 1 discloses a battery mounting structure used in electric vehicles and hybrid vehicles. This battery mounting structure includes a case that houses a plurality of battery modules for driving the vehicle on the underside of a floor panel of a vehicle interior. The plurality of battery modules are divided into a lower module and an upper module, and the case has a lower case member made of metal, a middle case member made of metal, and an upper case member for covering a predetermined area of ​​the upper surface of the middle case member from above. The lower module is fixed to the bottom of the lower case member, and the middle case member is fixed to the lower case member so as to cover the lower module from above, so that the lower module is housed watertight. The upper module is fixed in a state in which it is in close contact with the upper surface of the middle case member within a predetermined area. The upper case member is formed in a container shape having an opening at the bottom, and is fixed in a state in which it covers a predetermined area and the periphery of the opening is in close contact with the upper surface of the middle case member, so that the upper module is housed watertight. The lower case member is attached to the underside of the floor panel, so that the case is fixed to the vehicle.

[0003] Patent Document 2 discloses a battery pack device used in, for example, an electric vehicle, which is composed of batteries stacked in multiple stages. The battery pack device includes a first battery group composed of a plurality of batteries arranged on the same plane, and a second battery group composed of a plurality of batteries identical to the first battery group arranged on the same plane in the battery tray, which is stacked on the first battery group with a battery tray in between, and includes a battery pack body including a battery section in which the batteries are electrically connected to each other, and a body case that houses the battery section. The battery is rectangular and can be installed in a first position in which the height in the direction in which the second battery group overlaps with the first battery group is small, and in a second position in which the positions of the terminals of the battery in the overlapping direction are higher than the positions of the terminals in the first position. This battery pack device is characterized in that a first battery of a first battery group is arranged in a second position, a hole is formed in the battery tray through which the vicinity of the terminal of the first battery passes and the terminal of the first battery is exposed to the second battery group side, a second battery of the second battery group near the hole is arranged in the first position, and the first battery and second battery are electrically connected to each other by a connecting member having a fixed shape.

[0004] The battery pack housing contains the number of battery cells necessary to obtain the desired voltage. Lithium-ion batteries or nickel-metal hydride batteries are used as the battery cells. The battery cells are arranged in a roughly rectangular parallelepiped shape, and multiple battery cells are arranged in the limited space inside the housing. Since the battery cells generate heat due to chemical reactions during charging and discharging, it is important to efficiently release the heat emitted from the battery cells contained in a sealed state inside the housing to the outside. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-001451 A [Patent Document 2] JP 2006-080042 A Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of the above circumstances, and has an object to provide a battery pack that can efficiently release heat from battery cells to the outside. [Means for solving the problem]

[0007] One aspect of the present invention is a battery pack mounted on a hybrid system, comprising a battery module that supplies power to a motor generator of the hybrid system, a control circuit that controls the battery module, a housing that accommodates the battery module and the control circuit, and an insulating thermally conductive member provided between each of the battery module and the housing. Effect of the Invention

[0008] According to the present invention, it is possible to provide a battery pack capable of efficiently releasing heat from battery cells to the outside. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing a hybrid system. [Diagram 2] 1 is an external perspective view illustrating a battery pack according to an embodiment of the present invention; [Diagram 3] 1 is a partially exploded perspective view illustrating a battery pack according to an embodiment of the present invention; [Figure 4] 1 is a schematic cross-sectional view illustrating a battery pack according to an embodiment of the present invention; [Diagram 5] 4 is a perspective view illustrating a ceiling surface of a housing cover. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The embodiments described below are preferred specific examples of the present invention, and therefore various technically preferable limitations are applied to them, but the scope of the present invention is not limited to these aspects unless otherwise specified in the following description to the effect that the present invention is limited to them. In addition, in each drawing, similar components are given the same reference numerals, and detailed descriptions thereof are omitted as appropriate.

[0011] (Hybrid system) FIG. 1 is a block diagram showing a hybrid system. A battery pack 40 to which the housing according to this embodiment is applied is mounted in a hybrid system 10 shown in Fig. 1. The hybrid system 10 includes an engine 1, a motor generator 2, and the battery pack 40. The hybrid system 10 according to this embodiment further includes a DC / DC converter 70. The engine 1 is an internal combustion engine, for example, a diesel engine. The engine 1 is mounted in, for example, a vehicle (such as a passenger car or a small mobile object) or an industrial machine such as a construction machine or an agricultural machine.

[0012] The engine 1 is, for example, a multi-cylinder diesel engine such as a turbocharged high-output three-cylinder or four-cylinder engine. However, the engine 1 is not limited to a diesel engine. The engine 1 has an ECU (Engine Control Unit) 150. The ECU 150 controls the operation of the engine 1 and also controls the motor generator 2 and the DC / DC converter 70 by communicating with them via, for example, a CAN (Controller Area Network).

[0013] The motor generator 2 operates with power supplied from the battery pack 40 to support the engine 1 when power is required, such as when the vehicle in which the hybrid system 10 is mounted starts or accelerates. The motor generator 2 also uses regenerative braking or the like to convert the kinetic energy of the industrial machinery in which the hybrid system 10 is mounted into electrical energy to generate electricity.

[0014] The battery pack 40 includes a battery module 50, a positive contactor 75, a negative contactor 76, a current value detector 65, a temperature detector 67, a BMU (Battery Management Unit) 85, and a CMU (Cell Management Unit) 87. The battery module 50 is provided as a driving power source for the motor generator 2, and supplies power to the motor generator 2. The battery module 50 includes at least one battery cell 510. In the hybrid system 10 shown in FIG. 1, the battery module 50 includes a number of battery cells 510 required to obtain a voltage of, for example, 48V. An example of the battery cell 510 is a lithium ion battery (LiB). However, the battery cell 510 of this embodiment is not limited to a lithium ion battery. The battery module 50 includes a positive (+) terminal 51 and a negative (-) terminal 52.

[0015] The positive electrode side contactor 75 is provided in an electric circuit between the positive electrode terminal 51 of the battery module 50 and the motor generator 2. Specifically, as shown in Fig. 1, the positive electrode side contactor 75 is provided in positive electrode wirings 173, 174 that connect the positive electrode terminal 51 of the battery module 50 and the motor generator 2. In other words, the electric circuit between the positive electrode terminal 51 of the battery module 50 and the motor generator 2 includes the positive electrode wiring 173 and the positive electrode wiring 174. The positive electrode side contactor 75 is electrically connected to the ECU 150 by a signal line 181, and opens and closes the positive electrode wirings 173, 174 based on a control signal transmitted from the ECU 150 through the signal line 181.

[0016] The positive contactor 75 may be electrically connected to the BMU 85. In this case, the positive contactor 75 opens and closes the positive wirings 173, 174 based on a control signal transmitted from the BMU 85. In the description of the present embodiment, a case in which the positive contactor 75 is electrically connected to the ECU 150 by a signal line 181 will be taken as an example.

[0017] The negative contactor 76 is provided in an electric circuit between the negative terminal 52 of the battery module 50 and the motor generator 2. Specifically, as shown in Fig. 1, the negative contactor 76 is provided in a negative wiring 175 that connects the negative terminal 52 of the battery module 50 and the motor generator 2. In other words, the electric circuit between the negative terminal 52 of the battery module 50 and the motor generator 2 includes the negative wiring 175. The negative contactor 76 is electrically connected to the BMU 85 by a signal line 182, and opens and closes the negative wiring 175 based on a control signal transmitted from the BMU 85 through the signal line 182.

[0018] The negative contactor 76 may be electrically connected to the ECU 150. In this case, the negative contactor 76 opens and closes the negative wiring 175 based on a control signal transmitted from the ECU 150. In the description of the present embodiment, a case in which the negative contactor 76 is electrically connected to the BMU 85 by a signal line 182 will be taken as an example.

[0019] The BMU 85 is an example of a "control circuit" of the present invention. The BMU 85 controls the overall voltage of the battery module 50. That is, the BMU 85 is electrically connected to the ECU 150 by a signal line 193, and controls the negative contactor 76 based on a control signal transmitted from the ECU 150 through the signal line 193. The ECU 150 and the BMU 85 communicate with each other, for example, by a CAN, and monitor each other's states.

[0020] The BMU 85 also monitors the state of the battery module 50 and can detect an abnormality in the battery module 50. For example, the BMU 85 detects an overcharge (minor failure) abnormality or an overcharge (major failure) abnormality based on the voltage of the battery cell 510 acquired from the CMU 87. Alternatively, the BMU 85 detects an overdischarge (minor failure) abnormality or an overdischarge (major failure) abnormality based on the voltage of the battery cell 510 acquired from the CMU 87. Alternatively, the BMU 85 detects an overtemperature (minor failure) abnormality based on the temperature of the battery cell 510 acquired from the CMU 87. Alternatively, the BMU 85 detects an overcurrent abnormality based on a current value acquired from a current value detection unit 65 provided in the positive electrode wiring 174.

[0021] The CMU 87 is an example of the "control circuit" of the present invention. The CMU 87 monitors the state of the battery cells 510 included in the battery module 50 and sends the information to the BMU 85. When the battery module 50 includes a plurality of battery cells 510, the CMU 87 monitors the voltage of each battery cell 510 and sends information on the voltage of each battery cell 510 to the BMU 85 through a signal line 191. The CMU 87 also obtains information on the temperature of the battery cells 510 detected by the temperature detection unit 67 from a signal line 183 and sends the information on the temperature of the battery cells 510 to the BMU 85 through the signal line 191. The CMU 87 may be provided separately from the BMU 85 or may be provided integrally with the BMU 85.

[0022] As described above, the negative electrode wiring 175 electrically connects the negative electrode terminal 52 of the battery module 50 to the motor generator 2, and serves as the ground 100B. For example, the negative electrode wiring 175 is connected to the body of a vehicle or the like in which the hybrid system 10 is mounted, and is grounded. The positive electrode wiring 173 electrically connects the positive electrode terminal 51 of the battery module 50 to the motor generator 2, and also electrically connects the motor generator 2 to the DC / DC converter 70. When the battery module 50 is a 48V lithium-ion battery as in the hybrid system 10 shown in FIG. 1, the potential of the positive electrode wirings 173, 174 relative to the negative electrode wiring 175 is 48V.

[0023] The DC / DC converter 70 is electrically connected to the battery 80 via a positive wiring 171 and a negative wiring 172. An example of the battery 80 is a 12V lead-acid battery. The negative wiring 172 electrically connects the negative terminal 82 of the battery 80 to the DC / DC converter 70, and serves as a ground 100B. For example, the negative wiring 172 is connected to the body of a vehicle or the like in which the hybrid system 10 is mounted and is grounded. The positive wiring 171 electrically connects the positive terminal 81 of the battery 80 to the DC / DC converter 70. When the battery 80 is a 12V lead-acid battery as in the hybrid system 10 shown in FIG. 1, the potential of the positive wiring 171 relative to the negative wiring 172 is 12V.

[0024] As described above, the motor generator 2 uses regenerative braking or the like to convert the kinetic energy of the vehicle or the like in which the hybrid system 10 is mounted into electrical energy to generate electricity. The motor generator 2 supplies a voltage to the battery module 50 to charge the battery module 50, and also supplies a voltage to the battery 80 to charge the battery 80. Here, taking the hybrid system 10 shown in FIG. 1 as an example, the potential of the positive electrode wiring 173 relative to the negative electrode wiring 175 is 48V. That is, the generated voltage of the motor generator 2 is 48V. On the other hand, the potential of the positive electrode wiring 171 relative to the negative electrode wiring 172 is 12V. Therefore, the DC / DC converter 70 converts the voltage of 48V generated by the motor generator 2 into a voltage of 12V. As a result, the motor generator 2 can supply a voltage of 12V to the battery 80 via the DC / DC converter 70 to charge the battery 80.

[0025] Furthermore, the DC / DC converter 70 is electrically connected to the battery module 50 and the battery 80, and can perform charging and discharging between the battery module 50 and the battery 80 based on a control signal transmitted from the ECU 150. For example, the DC / DC converter 70 can discharge the battery module 50 and charge the battery 80 by converting the voltage and causing a constant current (e.g., 10 A) to flow from the battery module 50 to the battery 80. Alternatively, for example, the DC / DC converter 70 can discharge the battery 80 and charge the battery module 50 by converting the voltage and causing a constant current (e.g., 10 A) to flow from the battery 80 to the battery module 50.

[0026] The hybrid system 10 of this embodiment has the function of safely cutting off the electrical circuit that supplies power from the battery module 50 to the motor generator 2 when an abnormality occurs in the battery module 50 or when the entire hybrid system 10 is shut down.

[0027] For example, when the ignition switch is turned on, the ECU 150 transmits a control signal to the positive contactor 75 through a signal line 181 and executes control to close the positive contactor 75, thereby electrically connecting the positive wiring 174. The BMU 85 also executes control to close the negative contactor 76 based on a control signal transmitted from the ECU 150 through a signal line 193, thereby electrically connecting the negative wiring 175. This enables the battery module 50 to supply power to the motor generator 2.

[0028] On the other hand, for example, when the ignition switch is turned off, the ECU 150 transmits a control signal to the positive contactor 75 through a signal line 181 and executes control to open the positive contactor 75, thereby electrically cutting off the positive wiring 174. Also, the BMU 85 executes control to open the negative contactor 76 based on a control signal transmitted from the ECU 150 through a signal line 193, thereby electrically cutting off the negative wiring 175. As a result, the supply of power from the battery module 50 to the motor generator 2 is stopped.

[0029] Furthermore, when the BMU 85 detects, for example, an abnormality in the battery module 50, the ECU 150 transmits a first interruption signal R1 to the positive contactor 75 via a signal line 181 and executes control to open the positive contactor 75, thereby electrically interrupting the positive wiring 174. Furthermore, the BMU 85 transmits a second interruption signal R2 to the negative contactor 76 via a signal line 182 independently of a control signal transmitted from the ECU 150 and executes control to open the negative contactor 76, thereby electrically interrupting the negative wiring 175.

[0030] Alternatively, as described above, the ECU 150 and the BMU 85 communicate with each other and monitor each other's states. When the ECU 150 detects an abnormality in the BMU 85, the ECU 150 transmits a first interruption signal R1 to the positive contactor 75 via a signal line 181 and executes control to open the positive contactor 75, thereby electrically interrupting the positive wiring 174. On the other hand, when the BMU 85 detects an abnormality in the ECU 150, the BMU 85 transmits a second interruption signal R2 to the negative contactor 76 via a signal line 182 independently of a control signal transmitted from the ECU 150 and executes control to open the negative contactor 76, thereby electrically interrupting the negative wiring 175.

[0031] According to the hybrid system 10 described above, two contactors (in this embodiment, the positive electrode contactor 75 and the negative electrode contactor 76) are provided in an electric circuit (in this embodiment, the positive electrode wirings 173, 174 and the negative electrode wiring 175) that supplies electric power from the battery module 50 to the motor generator 2, and the ECU 150 controls the positive electrode contactor 75, and the BMU 85 controls the negative electrode contactor 76. Therefore, even if an abnormality occurs in the battery module 50 or in either the ECU 150 or the BMU 85, the hybrid system 10 according to this embodiment can cut off the electric circuit that supplies electric power from the battery module 50 to the motor generator 2. As a result, the hybrid system 10 can improve the safety of the battery module 50 that supplies electric power to the motor generator 2.

[0032] (Battery pack) FIG. 2 is an external perspective view illustrating the battery pack according to the present embodiment. FIG. 3 is a partially exploded perspective view illustrating the battery pack according to the present embodiment. FIG. 3 shows a state in which the housing cover 420 and the heat conductive member 600 of the housing 400 of the battery pack 40 are open. FIG. 4 is a schematic cross-sectional view illustrating the battery pack according to the present embodiment. The battery pack 40 includes a battery module 50, a control circuit including a BMU 85 and a CMU 87, and a housing 400 that houses the battery module 50 and the control circuit. The housing body 410 and the housing cover 420 are formed by casting using a metal material including aluminum, for example. A seal (not shown) is provided at the joint between the housing body 410 and the housing cover 420, and the inside of the housing 400 becomes watertight by covering the housing body 410 with the housing cover 420 and fastening and fixing them, for example, with screws.

[0033] The battery module 50 accommodated in the housing 400 has, for example, a plurality of battery cells 510. One battery module 50 may be accommodated in one housing 400, or a plurality of battery modules 50 may be accommodated in one housing 400.

[0034] The battery cells 510 are provided in a substantially rectangular parallelepiped shape having flat surfaces (upper surface 510a and bottom surface 510b) facing each other and four side surfaces 510c each having a smaller area than the upper surface 510a and the bottom surface 510b. The battery cells 510 are arranged side by side along the bottom surface 400a of the housing 400 such that the bottom surface 510b faces the bottom surface 400a.

[0035] The battery module 50 may have a plurality of battery cells 510. In this case, the plurality of battery cells 510 are preferably arranged side by side along the bottom surface 400a of the housing 400. The battery cells 510 may be arranged in a single stage in the housing 400, or in a plurality of stages. In the case of a plurality of stages, the battery cells 510 are preferably arranged such that the top surface portions 510a and the bottom surface portions 510b of two battery cells 510 in the stacking direction face each other.

[0036] Between the battery module 50 accommodated in the housing 400 and the housing 400, an insulating heat-conducting member 600 is provided. For example, a silicone sheet having insulating and heat-conducting properties is used for the heat-conducting member 600. The heat-conducting member 600 is disposed between the upper surface 510a of the battery cell 510 and the ceiling surface 420a of the housing cover 420 (housing 400) facing the bottom surface 400a of the housing 400. It is preferable that the heat-conducting member 600 contacts each of the upper surface 510a of the battery cell 510 and the ceiling surface 420a of the housing cover 420. Note that some member may be interposed between the heat-conducting member 600 and the upper surface 510a, and between the heat-conducting member 600 and the ceiling surface 420a.

[0037] The battery cell 510 is disposed so that the bottom surface portion 510b faces the bottom surface 400a of the housing 400, and thus the upper surface portion 510a of the battery cell 510 faces the ceiling surface 420a of the housing cover 420. In the battery cell 510, the area of ​​the upper surface portion 510a is larger than the area of ​​the side surface portion 510c, so that the upper surface portion 510a and the heat conductive member 600 come into contact with each other (including the case where they come into contact with each other through a member), and thus the heat generated in the battery cell 510 can be effectively transferred to the heat conductive member 600. In addition, the heat conductive member 600 comes into contact with the ceiling surface 420a of the housing cover 420 (including the case where they come into contact with each other through a member), and thus the heat transferred from the battery cell 510 to the heat conductive member 600 can be effectively transferred to the housing cover 420, and can be easily released from the housing 400 to the outside.

[0038] The battery pack 40 may have a plurality of battery modules 50. In this case, the plurality of battery modules 50 are preferably arranged side by side along the bottom surface 400a of the housing 400. This is advantageous in terms of heat dissipation because the upper surface portions 510a of the battery cells 510 in the plurality of battery modules 50 do not overlap.

[0039] In a configuration in which a plurality of battery modules 50 are arranged side by side, the thermally conductive member 600 may have a portion disposed between adjacent battery modules 50 among the plurality of battery modules 50. By disposing a portion of the thermally conductive member 600 between adjacent battery modules 50, heat is easily transferred to the thermally conductive member 600 not only from the upper surface portion 510a of the battery cell 510 but also from a portion of the side surface portion 510c.

[0040] FIG. 5 is a perspective view illustrating an example of a ceiling surface of the housing cover. The housing cover 420 is formed by casting, for example, aluminum. The ceiling surface 420a of the housing cover 420 has a first area A1 facing the battery module 50 (see FIG. 3) and a second area A2 other than the first area A1. In the housing cover 420, it is preferable that the surface roughness of the first area A1 is lower than that of the second area A2. For example, in a state in which the housing cover 420 is formed by casting, the surface of the mold by casting is transferred to both the first area A1 and the second area A2, and the surface roughness is relatively rough. Therefore, the first area A1 is subjected to cutting or the like to make the surface roughness of the first area A1 lower than that of the second area A2. This improves the adhesion between the first area A1 and the heat conductive member 600 on the ceiling surface 420a of the housing cover 420, and heat can be more effectively transferred from the heat conductive member 600 to the housing cover 420.

[0041] According to this embodiment, it is possible to provide a battery pack 40 that can efficiently release heat from the battery cells 510 to the outside.

[0042] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the claims. For example, the configurations of the above embodiments can be partially omitted or arbitrarily combined in a manner different from the above. [Explanation of symbols]

[0043] 1...engine, 2...motor generator, 10...hybrid system, 40...battery pack, 50...battery module, 51...positive terminal, 52...negative terminal, 65...current detection section, 67...temperature detection section, 70...DC / DC converter, 75...positive contactor, 76...negative contactor, 80...battery, 81...positive terminal, 82...negative terminal, 85...BMU, 87...CMU, 100B...ground, 150...ECU, 171...positive wiring, 172...negative wiring, 173... Positive wiring, 174... positive wiring, 175... negative wiring, 181... signal line, 182... signal line, 183... signal line, 191... signal line, 193... signal line, 400... housing, 400a... bottom surface, 410... housing main body, 420... housing cover, 420a... ceiling surface, 510... battery cell, 510a... upper surface portion (flat portion), 510b... bottom surface portion (flat portion), 510c... side surface, 600... heat conductive member, A1... first region, A2... second region, R1... first shutoff signal, R2... second shutoff signal

Claims

1. A battery pack mounted in a hybrid system, a battery module for supplying power to a motor generator of the hybrid system; A control circuit for controlling the battery module; a housing that accommodates the battery module and the control circuit; a thermally conductive member having insulating properties, the thermally conductive member being provided between the battery module and the housing.

2. the battery module includes at least one battery cell; The battery cell is provided in a substantially rectangular parallelepiped shape having planar portions facing each other and four side portions each having an area smaller than that of the planar portions, The battery cell is arranged so that the planar portion is exposed, The battery pack according to claim 1 , wherein the thermally conductive member is disposed so as to be in contact with the planar portion of the battery cell and an inner surface of the housing.

3. 2 . The battery pack according to claim 1 , wherein a surface roughness of a first region of the ceiling surface of the housing that faces the battery module is lower than a surface roughness of a second region of the ceiling surface of the housing other than the first region.

4. The battery pack of claim 1 , wherein the housing is formed of a metallic material including aluminum.

5. The battery module includes a plurality of battery cells. The battery pack according to claim 1 , wherein the plurality of battery cells are arranged side by side along a bottom surface of the housing and stacked in a normal direction to the bottom surface of the housing.

6. A battery module according to the present invention includes: The plurality of battery modules are arranged side by side along a bottom surface of the housing, The battery pack according to claim 1 , wherein the thermally conductive member has a portion disposed between adjacent battery modules among the plurality of battery modules.

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