Connection method and battery pack

Abstract

To reduce the possibility of electric shock when reconnecting after battery pack assembly, a connection method is provided that allows the busbar and voltage detection line to be connected. [Solution] The connection method according to this disclosure is a method for connecting a busbar 12 and a voltage detection wire 13 in a battery pack. In this connection method, the voltage detection wire 13 is joined to the busbar 12 housed in a busbar case 11 made of insulating material, and the busbar 12 and the voltage detection wire 13 are pressed between the busbar case 11 and a spacer 15 made of insulating material, and the spacer 15 is fixed to the busbar case 11, thereby bringing the busbar 12 and the voltage detection wire 13 into close contact.

Description

Technical Field

[0001] The present disclosure relates to a connection method and a battery pack.

Background Art

[0002] Patent Document 1 describes a connection structure between an insulated wire and a conductor part, which can prevent the insulated wire from detaching from a wire fixing part that fixes the insulated wire by protecting the insulation coating of the insulated wire from heat when joining the conductor wires of the insulated wire.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when assembling a battery pack using the technology described in Patent Document 1, caution against electric shock is required when re - joining a voltage detection line, which is an insulated wire, and a bus bar, which is a conductor part, for repair. Therefore, development of a technology for connecting a bus bar and a voltage detection line is desired so as to reduce the possibility of electric shock when re - connecting them after assembling the battery pack.

[0005] The present disclosure has been made in view of the above - described actual situation, and provides a connection method capable of connecting a bus bar and a voltage detection line so as to reduce the possibility of electric shock when re - connecting after assembling a battery pack, and a battery pack thereof.

Means for Solving the Problems

[0006] The connection method according to this disclosure is a method for connecting a busbar and a voltage detection line in a battery pack, wherein the voltage detection line is joined to the busbar housed in a busbar case made of an insulating material, and the busbar and the voltage detection line are pressed between the busbar case and a spacer made of an insulating material, and the spacer is fixed to the busbar case, thereby bringing the busbar and the voltage detection line into close contact.

[0007] The battery pack according to this disclosure comprises a busbar, a busbar case made of an insulating material for housing the busbar, a voltage detection wire connected to the busbar within the busbar case, and a spacer made of an insulating material fixed to the busbar case, wherein the busbar and the voltage detection wire are tightly fixed between the busbar case and the spacer. [Effects of the Invention]

[0008] According to this disclosure, a connection method and a battery pack can be provided that allows for the connection of a busbar and a voltage detection line in such a way as to reduce the possibility of electric shock when reconnecting after the battery pack has been assembled. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic exploded perspective view showing one example of a battery pack configuration in which a busbar and a voltage detection line are connected using the connection method according to the embodiment. [Figure 2] Figure 1 is a schematic perspective view showing an example of a busbar module in a battery pack. [Figure 3] Figure 1 is a schematic diagram showing a partial configuration example of the circuit in the battery pack. [Figure 4] This is a flowchart illustrating an example of a connection method according to the embodiment. [Figure 5] Figure 4 shows a schematic diagram illustrating an example of connection using the connection method and an example of connection using the connection method in the comparative example. [Figure 6] Figure 4 is a schematic diagram showing the connection status based on the connection method. [Modes for carrying out the invention]

[0010] The present invention will be described below through embodiments, but the claims are not limited to the following embodiments. Furthermore, not all of the configurations described in the embodiments are necessarily essential for solving the problem.

[0011] (Embodiment) Prior to describing the connection method according to this embodiment, an example of a battery pack manufactured by the connection method according to this embodiment will be described using Figures 1 to 3. Figure 1 is a schematic exploded perspective view showing an example of a battery pack in which the busbar and voltage detection line are connected by the connection method according to this embodiment. Figure 2 is a schematic perspective view showing an example of a busbar module in the battery pack of Figure 1. Figure 3 is a schematic diagram showing an example of a part of the circuit configuration in the battery pack of Figure 1.

[0012] The battery pack 1 shown in Figure 1 has a structure in which multiple batteries are stacked, and is also called a battery module. The battery pack 1 may include, for example, a main body 100 and a cover 200.

[0013] The cover portion 200 can be configured to be attached to the main body portion 100 by engaging, for example, a first cover portion 201 and a second cover portion 202, as shown in the figure. The second cover portion 202 is mainly a cover that covers the battery cooling blower assembly, which will be described later, and the first cover portion 201 is a cover that covers other parts.

[0014] The main unit 100 comprises a housing 101 and a first battery stack 102a, a second battery stack 102b, a first busbar module 103a, a second busbar module 103b, and a battery ECU assembly 104, all mounted on the housing 101. ECU stands for Electronic Control Unit.

[0015] The first battery stack 102a and the second battery stack 102b are each composed of a plurality of batteries stacked together. The batteries to be stacked can be, for example, hybrid batteries used for motor driving among the two types of batteries mounted on a hybrid vehicle, but other types of batteries may also be used.

[0016] The first bus bar module 103a and the second bus bar module 103b are battery bus bar modules each including a bus bar attached to the electrodes of the batteries to be stacked in the first battery stack 102a and the second battery stack 102b, respectively. As illustrated in FIG. 2, the bus bar module 103 provided in the battery pack 1 can be configured to include the first bus bar module 103a, the second bus bar module 103b, and connection cables for connecting other parts thereto. Each of the bus bar modules 103a and 103b includes a bus bar case serving as its case and a bus bar housed in the bus bar case. The bus bar case can be formed of an insulating material such as resin.

[0017] In FIG. 2, a portion for joining between batteries corresponding to the individual bus bars in the first bus bar module 103a and the second bus bar module 103b is illustrated as a joining portion 10. Also, as illustrated in FIG. 3, the bus bar 12 at each joining portion 10 connects the positive electrode and the negative electrode between the stacked batteries.

[0018] Voltage detection lines are connected to the first bus bar module 103a and the second bus bar module 103b at positions indicated by star marks in FIG. 3, and the battery ECU assembly 104 detects the voltage of each battery via each voltage detection line. The method of connecting the bus bar and the voltage detection lines will be described later with reference to FIGS. 4 to 6.

[0019] Note that the battery pack 1 may include only one battery stack, or may include three or more battery stacks, and a bus bar module having a corresponding configuration may be attached thereto.

[0020] The battery ECU assembly 104 is connected to the first bus bar module 103a, the second bus bar module 103b, etc., and includes an ECU that controls power supply from the battery to the load and charging of the battery. The ECU can perform control based on the voltage of each battery detected via each voltage detection line.

[0021] Further, the main body 100 includes a battery junction block assembly 105, a service plug grip 106, and a battery cooling blower assembly 107 that are attached to the housing 101.

[0022] As shown in FIG. 3, the BJB assembly 105 is a connection box including relays such as an SMR (System Main Relay) 105a and fuses. The BJB assembly 105 connects between the first battery stack 102a, the second battery stack 102b, and the power cable 105b. The SMR is a relay inserted into a high-voltage circuit on the way of sending high power from the first battery stack 102a and the second battery stack 102b to a driving inverter or the like, and opens and closes the main power.

[0023] The service plug grip 106 cuts off the high voltage at an intermediate position between the first battery stack 102a and the second battery stack 102b by being removed during inspection and maintenance, ensuring the safety of the work. In the example of FIG. 3, a fuse 109 is provided between the second battery stack 102b and the service plug grip 106.

[0024] The battery cooling blower assembly 107 is connected to the BJB assembly 105 and receives power supply. The battery cooling blower assembly 107 includes a blower that blows air to cool the battery pack 1. In addition, the main body 100 includes an exhaust port 108 for the blown air.

[0025] An example of the connection method according to this embodiment (hereinafter referred to as "this connection method") will be explained using Figures 4 to 6. Figure 4 is a flowchart illustrating an example of this connection method. Figure 5 is a schematic diagram showing an example of connection using the connection method in Figure 4 and an example of connection using the connection method in the comparative example. Figure 6 is a schematic diagram showing the connection state using the connection method in Figure 4.

[0026] In this connection method, as shown in Figure 4, the voltage detection wire is first joined to the busbar housed in the busbar case (step S1). This joining is performed by, for example, ultrasonic welding, but other joining methods may also be used.

[0027] Figure 5 will be used to explain the busbars and voltage detection lines to be connected. As shown in Figure 5, which is a top view of one of the connection points 10 shown in Figure 2, the busbar 12 is housed in a busbar case 11 made of insulating material and is provided to electrically connect each battery 21. Each battery 21 refers to two adjacent batteries included in the first battery stack 102a and the second battery stack 102b. A separator 22 is provided between adjacent batteries 21. The busbar case 11 has a structure that fixes the busbar 12 so that it does not move out of the busbar case 11 when the busbar 12 is housed in it.

[0028] The busbar 12 and the electrodes of each battery are joined at each connection point 12s by laser bonding or the like. The voltage detection wire 13 comprises a wire 13a and an insulating coating 13b covering the wire 13a, with the tip of the wire 13a exposed at the connection point with the busbar 12.

[0029] In step S1, the end of the electric wire 13a is joined to the busbar 12. The busbar 12 can have a shape such that the part where the voltage detection wire 13 is joined is higher than the part where it is joined to the battery 21, as shown in Figure 5 as the part corresponding to the cross-section of the AA wire at the joining part 10A. In step S1, it is also preferable to form an insulating member 14 by application or other means at the position of the end of the electric wire 13a and the position of the insulating coating 13b to reinforce the fixation with the busbar 12.

[0030] Next, as shown as the joint portion 10A in Figure 5, a spacer 15 is inserted on the busbar 12 and voltage detection line 13 in the busbar case 11 (step S2), and the two are brought into close contact (step S3). The spacer 15 can be made of an insulating material such as resin. Note that the spacer 15 is shown in a simplified form at the joint portion 10A, and a detailed example of its shape will be described later using Figure 6.

[0031] The structure for achieving this close contact will be described later with reference to Figure 6, but in step S3, the bus bar 12 and the voltage detection wire 13 are fixed in a pressed position between the bus bar case 11 and the spacer 15, thereby bringing the bus bar 12 and the voltage detection wire 13 into close contact.

[0032] In the example of joint portion 10A, as shown in the enlarged view of a part thereof, the upper surface of the insulating member 14 applied to the tip of the electric wire 13a and the lower surface of the spacer 15 are in contact, and the spacer 15 causes the busbar 12 and the tip of the electric wire 13a of the voltage detection wire 13 to be in close contact. Although not shown, at the same time as this contact, the upper surface of the insulating member 14 applied to the insulating coating 13b and the lower surface of the spacer 15 may also be in contact, causing the busbar 12 and the insulating coating 13b of the voltage detection wire 13 to be in close contact as well.

[0033] An example of a structure for achieving the aforementioned tight seal will be explained using Figure 6. In Figure 6, joint 10B is shown as a top view of joint 10A in Figure 5, and joint 10C is shown showing the insertion of spacer 15 during the formation of joint 10B. In addition, in Figure 6, the cross-sectional view of the BB line at joint 10B is shown as joint 10BB, and the cross-sectional view of the CC line at joint 10B is shown as joint 10BC.

[0034] As shown in the joint portion 10B, the spacer 15 may be provided with spacer-side engaging portions 15b, 15c, and 15d on its main body portion 15a for engaging with the busbar case 11. The circular or elliptical portion shown in the center of the main body portion 15a in the joint portion 10B is a mark or protrusion that serves as a guide for the position to press when the worker stores the spacer 15 in the busbar case 11.

[0035] The busbar case 11 may be provided with a plurality of case-side engaging portions 11b, 11c, and 11d on the inner circumference side of the upper end opening of its main body portion 11a. The upper end opening of the busbar case 11 can be an opening that accommodates the busbar 12 and serves as an insertion opening for the spacer 15. As exemplified by the joining portion 10C, the case-side engaging portions 11b and 11c can be recesses formed in a direction perpendicular to the direction in which the busbar 12 is joined to the battery 21 and also perpendicular to the stacking direction of the battery 21. Furthermore, as exemplified by the joining portions 10BB and 10BC, the case-side engaging portion 11d can be a portion having a projection toward the bottom surface side of the busbar case 11.

[0036] Furthermore, the spacer 15 may be equipped with spacer-side engaging portions 15b, 15c, and 15d that engage with the case-side engaging portions 11b, 11c, and 11d, respectively.

[0037] Then, as shown in the joint portion 10C, the spacer-side engaging portions 15b and 15c are inserted into the case-side engaging portions 11b and 11c, respectively, and the main body portion 15a is pushed toward the bottom surface of the busbar case 11, thereby fixing the spacer 15 to the busbar case 11. With this fixing, the spacer 15 is fixed as shown in the joint portions 10BB and 10BC. Note that in the joint portion 10C, reference numeral 12t indicates a part of the busbar 12 where the voltage detection line 13 is joined, which has been omitted from the illustration.

[0038] In this engagement, the elastic force of the spacer 15 is utilized to fix the spacer 15 to the busbar case 11, applying a load to the voltage detection wire 13, and fixing the busbar 12 and the voltage detection wire 13 in a pressed state between the busbar case 11 and the spacer 15. This fixing allows the busbar 12 and the voltage detection wire 13 to be in close contact.

[0039] In this way, when the spacer 15 is positioned to fill the opening space of the busbar case 11, the elastic force generated by the spacer 15 creates a pressing state, that is, a load can be applied. The material of the spacer 15 should be determined from the viewpoint of this elastic force and ease of attachment to the busbar case 11.

[0040] The shapes of the spacer-side engaging portion and the case-side engaging portion are not limited to the illustrated examples. For example, the case-side engaging portions 11b and 11c may also be formed to have projections that extend toward the bottom surface of the busbar case 11, similar to the case-side engaging portion 11d. In that case, the case-side engaging portions 15b and 15c may have projections that extend from the bottom surface of the busbar case 11 toward the upper end opening when the main body portion 15a of the spacer 15 is housed in the busbar case 11.

[0041] Furthermore, the shape and number of the spacer-side engaging portion and the case-side engaging portion are not limited to three; multiple spacer-side engaging portions can be engaged with multiple case-side engaging portions to press and fix the spacer 15 to the busbar case 11. In other words, the shape and number of the spacer-side and case-side engaging portions should be such that when the main body portion 15a of the spacer 15 is housed and fixed in the busbar case 11, the busbar 12 and the voltage detection line 13 are pressed and clamped between the main body portion 15a and the bottom surface of the busbar case 11.

[0042] Next, to explain the effects of this embodiment, a comparative example will be given. The connection method of the comparative example described here is a method in which a spacer is not provided in the connection method of this embodiment. The joint portion connected by the connection method of the comparative example is the portion shown as joint portion 10Ac in Figure 5. At joint portion 10Ac, as shown in the enlarged view of a part thereof, a gap FL is created between the busbar 12 and the tip of the wire 13a of the voltage detection line 13.

[0043] In contrast, in this embodiment, as shown in the enlarged view of a part of the joint portion 10A in Figure 5, there is no gap FL between the busbar 12 and the tip of the wire 13a of the voltage detection line 13, and the two are in close contact. Therefore, according to this embodiment, the connection between the busbar 12 and the voltage detection line 13 can be made stronger compared to the comparative example.

[0044] Furthermore, in the comparative example, the upper end opening of the busbar case 11 remains as is, so there is a risk of electric shock when reconnecting the busbar 12 and the voltage detection wire 13 after the battery pack is assembled. More specifically, after the battery pack is completed and distributed to the market, or during inspection after completion, poor connections between the busbar 12 and the voltage detection wire 13 may be discovered due to poor crimping of the voltage detection wire 13 of each battery cell. However, even if such a connection defect is discovered, the busbar 12 cannot be replaced because it is welded to the battery cell. Therefore, in the comparative example, when repairing, i.e., reconnecting, the connection between the busbar 12 and the voltage detection wire 13, the cover part 200 must be removed first, but since the repair area is a live part, there is a risk of electric shock during the process of removing the cover part 200 or after it has been removed.

[0045] In contrast, the battery pack 1 according to this embodiment has a spacer 15 positioned at the upper opening of the busbar case 11 to ensure this tight seal. Therefore, in the battery pack 1, when reconnecting the busbar 12 and the voltage detection wire 13 after assembly, the live parts are covered by the spacer 15 when the cover portion 200 is removed, thus reducing the possibility of electric shock. In other words, according to this embodiment, even if a faulty crimping of the voltage detection wire of the battery cell is discovered after the battery pack 1 is completed, it can be safely repaired with respect to the possibility of electric shock.

[0046] As described above, in the connection method according to this embodiment, a spacer 15 made of insulating material is used to tightly fix the busbar 12 and the voltage detection line 13. Therefore, according to the connection method according to this embodiment, the possibility of electric shock when reconnecting the busbar 12 and the voltage detection line 13 after the battery pack has been assembled can be reduced.

[0047] Furthermore, as illustrated in the joint section 10B, positioning the spacer 15 to cover the upper end opening of the busbar case 11 can further reduce the possibility of electric shock during repairs. However, even if the spacer 15 only covers a portion of the upper end opening, the possibility of electric shock can still be reduced.

[0048] Furthermore, since the battery pack 1 secures the spacer 15 using the concave portion of the busbar case 11, it can be said to be space-efficient. In addition, because the battery pack 1 has a structure in which the spacer 15 is placed at the upper opening of the busbar case 11, it can be said that electric shock prevention measures can be implemented efficiently using space.

[0049] Furthermore, in this embodiment, the connection point between the busbar 12 and the voltage detection line 13 can be located on top of the busbar 12 inside the busbar case 11. Therefore, according to this embodiment, the connection point between the busbar 12 and the voltage detection line 13 does not need to be located outside the busbar case 11, such as at a location separated from the busbar 12, and no space is required for that purpose.

[0050] Furthermore, the battery pack 1 connected using the connection method described above will have the following configuration. Specifically, the battery pack 1 comprises a busbar 12, a busbar case 11 made of insulating material for housing the busbar 12, a voltage detection wire 13 connected to the busbar 12 within the busbar case 11, and a spacer 15 made of insulating material. Here, the spacer 15 will be fixed to the busbar case 11. In addition, the busbar 12 and the voltage detection wire 13 will be tightly fixed between the busbar case 11 and the spacer 15.

[0051] This configuration reduces the possibility of electric shock when reconnecting the battery pack 1 after assembly.

[0052] Furthermore, as described above, the battery pack 1 has a busbar case 11 with multiple case-side engaging parts, and the spacer 15 has multiple spacer-side engaging parts that engage with the case-side engaging parts. By adopting this configuration, the battery pack 1 can be easily fixed or removed during manufacturing or repair of the battery pack 1.

[0053] (Other embodiments) It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. For example, the battery pack, busbar, and voltage detection line described in the above embodiments do not need to be configured, shaped, or arranged in any way, as long as they function as a battery pack, busbar, and voltage detection line, respectively. The battery pack described in the above embodiments is not limited to a battery pack equipped with a hybrid battery installed in a hybrid vehicle, but may also be a battery pack installed as a battery in an electric vehicle, or a battery pack installed in other types of vehicles such as motorcycles, trains, and ships. [Explanation of Symbols]

[0054] 1 Battery pack, 10, 10A, 10B, 10BB, 10BC, 10C connection points, 11 Busbar case, 11a Main body, 11b, 11c, 11d Case-side engagement parts, 12 Busbar, 12s Connection point, 13 Voltage detection wire, 13a Wire, 13b Insulation coating, 14 Insulating material, 15 Spacer, 15a Main body, 15b, 15c, 15d Spacer-side engagement parts, 21 Battery, 22 Separator, 100 Main body, 101 Housing, 102a First battery stack, 102b Second battery stack, 103a First busbar module, 103b Second busbar module, 104 Battery ECU assembly, 105 Battery junction block assembly, 106 Service plug grip, 107 Battery cooling blower assembly, 108 Exhaust port, 109 Fuse, 200 Cover section, 201 First cover section, 202 Second cover section.

Claims

1. A method for connecting a busbar and a voltage detection line in a battery pack, The voltage detection wire is connected to the busbar housed in a busbar case made of insulating material. The busbar and the voltage detection wire are pressed against each other between the busbar case and a spacer made of insulating material, and the spacer is fixed to the busbar case, thereby bringing the busbar and the voltage detection wire into close contact. Connection method.

2. The busbar case is provided with a case-side engaging portion on the inner circumference side of the upper end opening. The spacer is fixed to the busbar case by engaging the multiple spacer-side engaging portions provided on the spacer with the case-side engaging portions. The connection method according to claim 1.

3. The spacer is positioned to close the upper end opening of the busbar case. The connection method according to claim 1 or 2.

4. Bus bar and, A busbar case made of insulating material for housing the aforementioned busbar, Within the busbar case, a voltage detection line connected to the busbar, A spacer made of insulating material is fixed to the busbar case, Equipped with, The busbar and the voltage detection line are tightly fixed between the busbar case and the spacer. Battery pack.

5. The busbar case is provided with a case-side engaging portion on the inner circumference side of the upper end opening. The spacer comprises a plurality of spacer-side engaging portions that engage with the case-side engaging portion. The battery pack according to claim 4.

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