JP7852809B2 - Battery pack - Google Patents

Description

This invention relates to a battery pack.

Electric vehicles, such as electric cars and hybrid vehicles, which use a motor as their power source, are equipped with a battery pack that supplies power to the motor.
The battery pack comprises a battery pack consisting of multiple battery modules, an electrical unit for controlling the battery pack, and a waterproof and airtight case that houses the battery pack and the electrical unit.
Furthermore, the case is equipped with a pressure reducing valve that opens when the internal pressure of the case rises due to the high-temperature gas generated when thermal runaway occurs in the battery pack, thereby suppressing the rise in internal pressure (see Patent Document 1).
In recent years, the UN safety standard (UN R100-03) for battery pack safety certification requires that the battery pack detect the generation of high-temperature gases that occur when the batteries overheat, and notify the crew of the battery pack malfunction.
Therefore, for example, a pressure sensor that detects the internal pressure of the battery pack could be installed, and a battery monitoring ECU installed in the battery pack could determine whether or not there is an abnormality in the battery pack based on the internal pressure detected by the pressure sensor and notify the user.

Japanese Patent Application Publication No. 2022-103526

However, with the above configuration, a pressure sensor must be newly installed in addition to the pressure reducing valve, which is disadvantageous in terms of reducing the manufacturing cost of the battery pack.
This invention has been made in view of the above circumstances, and aims to provide a battery pack that is advantageous in reliably detecting the internal pressure of the battery pack while suppressing manufacturing costs.

To achieve the above objective, one embodiment of the present invention provides a battery pack comprising a case for housing a battery pack, and a pressure reducing valve provided in the case that opens when the internal pressure of the case rises to suppress the rise in internal pressure, wherein the battery pack is further comprising a wiring section body provided from the case to the pressure reducing valve and which is disconnected when the pressure reducing valve opens, and a battery monitoring ECU that detects the occurrence of an abnormality in the battery pack by detecting the disconnection of the wiring section body.
One embodiment of the present invention is characterized in that the pressure reducing valve is configured to include an opening provided in the case and a waterproof membrane that seals the opening, the pressure reducing valve is opened by the rupture of the waterproof membrane, and the wiring section body is configured to include a waterproof membrane wiring section formed in the waterproof membrane that is disconnected when the waterproof membrane ruptures.
In one embodiment of the present invention, the waterproof membrane wiring section is provided so as to pass through the central part of the waterproof membrane, and the waterproof membrane wiring section is configured to include a connector interposed in the waterproof membrane wiring section.
The connection of the connector is released when the waterproof membrane is ruptured.
In one embodiment of the present invention, the waterproof membrane wiring section is composed of a wiring portion extending from the edge to the central part of the waterproof membrane, and the wiring section body is located at the end of the wiring portion in the central part,
The device is configured to include a first wiring section that extends toward the case side away from the waterproof membrane, a connector is interposed in the first wiring section, and the connection of the connector is released when the waterproof membrane is ruptured.
One embodiment of the present invention comprises a pressure reducing valve comprising an opening wall portion provided in the case and forming an opening, and a valve body that is constantly biased in a direction to close the opening and separates from the opening wall portion to open the opening when the internal pressure of the case rises, and the wiring unit body comprising a valve body conductive portion provided on the valve body and an opening conductive portion provided on the opening wall portion and connected to the battery monitoring ECU, wherein the valve body conductive portion and the opening conductive portion are connected when the valve body closes the opening, and the connection between the valve body conductive portion and the opening conductive portion is released when the valve body opens the opening.
One embodiment of the present invention is characterized in that the valve body conductive portion is formed around the entire circumference of the outer periphery of the valve body, the opening conductive portion is provided separated from each other in the circumferential direction of the opening wall and is connected to the battery monitoring ECU, and includes a first opening conductive portion and a second opening conductive portion that are connected to the valve body conductive portion when the valve body closes the opening.
One embodiment of the present invention is characterized in that at least a portion of the wiring section body is configured to include a portion formed of a conductive thin film.

According to one embodiment of the present invention, a wiring section body is provided that extends from the case to the pressure reducing valve and is disconnected when the pressure reducing valve is opened. The battery monitoring ECU connected to the wiring section body detects the disconnection of the wiring section body, thereby detecting an abnormality in the battery pack.
Therefore, since there is no need to install a pressure sensor to detect the internal pressure of the case, which was previously required, manufacturing costs can be reduced, and the battery monitoring ECU has an advantage in that it can reliably detect the internal pressure of the battery pack by detecting a break in the wiring unit, just as it would if a pressure sensor were installed.
Furthermore, if the pressure reducing valve is opened by the rupture of a waterproof membrane that seals an opening in the case, and the waterproof membrane wiring formed on the waterproof membrane is disconnected when the waterproof membrane ruptures, then the waterproof membrane wiring is reliably disconnected almost simultaneously with the rupture of the waterproof membrane, which is advantageous for the battery monitoring ECU to reliably detect the internal pressure of the battery pack.
Furthermore, if the waterproof membrane wiring section is configured to include a connector interposed within the waterproof membrane wiring section, and the connector is released when the waterproof membrane ruptures, the connector can be easily released when the waterproof membrane ruptures due to an increase in internal case pressure. This makes it easier for the wiring section itself to break when the waterproof membrane ruptures, which is advantageous for the battery monitoring ECU to reliably detect the internal pressure of the battery pack.
Furthermore, if the wiring unit body includes a first wiring unit that extends toward the case side away from the waterproof membrane, and a connector is interposed in the first wiring unit, and the connection of the connector is released when the waterproof membrane is ruptured, then when the waterproof membrane is ruptured due to an increase in internal case pressure, the connection of the connector is easily released. This makes it easier for the wiring unit body to break when the waterproof membrane is ruptured, which is advantageous for the battery monitoring ECU to reliably detect the internal pressure of the battery pack.
Furthermore, if the wiring unit body includes a valve body conductive portion provided on the valve body and an opening conductive portion provided on the opening wall, and the valve body conductive portion and the opening conductive portion are connected when the valve body closes the opening, and the connection between the valve body conductive portion and the opening conductive portion is released when the valve body opens the opening, then when the valve body opens the opening due to an increase in internal case pressure, the connection between the valve body conductive portion and the opening conductive portion is easily and reliably released, causing the wiring unit body to be easily and reliably disconnected. This is advantageous for the battery monitoring ECU to reliably detect the internal pressure of the battery pack.
Furthermore, if the valve body conductive portion is formed around the entire circumference of the outer periphery of the valve body, and the opening conductive portions are provided separated from each other in the circumferential direction of the opening wall portion and each connected to the battery monitoring ECU, and the valve body is configured to include a first opening conductive portion and a second opening conductive portion that are connected to the valve body conductive portion when the valve body closes the opening, then regardless of the relative rotational position of the valve body and the opening around the axis, the valve body conductive portion and the first opening conductive portion and the second opening conductive portion will be reliably connected when the valve body closes the opening.
Therefore, when assembling the pressure reducing valve, there is no need to align the valve body's conductive section with the first and second conductive openings, and a rotation prevention mechanism to prevent the valve body from rotating is also unnecessary. This simplifies the assembly of the pressure reducing valve and is advantageous in reducing the cost of the battery pack.
Furthermore, if the wiring unit itself includes a portion formed of a conductive thin film, the wiring unit itself is more likely to break when the waterproof film is damaged, which is advantageous for the battery monitoring ECU to reliably detect the internal pressure of the battery pack.
Furthermore, if the wiring unit body includes a portion formed of a conductive thin film, even if there is some misalignment between the valve body conductive portion and the opening conductive portion when the valve body is closing the opening, the wiring unit body will not break, which is advantageous in preventing the battery monitoring ECU from mistakenly detecting that the wiring unit body has broken.

This is a cross-sectional view of the pressure reducing valve and its surrounding portion of a battery pack according to the first embodiment. This is a view of the waterproof membrane as seen through arrow A in Figure 1. This is a flowchart showing the operation of the battery pack according to the first embodiment. This is a cross-sectional view of the pressure reducing valve and its surrounding portion of a battery pack according to a second embodiment. Figure 4 is a view of the waterproof membrane as seen through arrow A. This is a cross-sectional view of the pressure reducing valve and its surrounding portion of a battery pack according to a third embodiment. Figure 6 is a view of the waterproof membrane as seen through arrow A. This is a cross-sectional view of the pressure reducing valve and its surrounding portion of a battery pack according to the fourth embodiment. Figure 8 is a view of the valve body as indicated by arrow A. Figure 8 is a view taken along arrow A, showing a modified example of the valve body's electrical connection. This is a view taken along arrow A, showing another modified example of the valve body's electrical connection in Figure 8.

(First Embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The battery pack according to this embodiment is applied to electric vehicles that use a motor as a power source, such as electric vehicles that use only a motor as a power source, hybrid vehicles, or plug-in hybrid vehicles that can be externally charged or externally powered, and is used to supply power to the motor.

As shown in Figure 1, the battery pack 10 is composed of a battery pack (not shown), an electrical component including a battery monitoring ECU (Electronic Control Unit) 12, a case 16 housing the battery pack and the electrical component, a pressure reducing valve 18A, and a wiring unit body 20A.
A battery pack is composed of multiple battery modules connected together, and each battery module is composed of multiple battery cells connected together.
The battery cell is a secondary battery such as a lithium-ion battery. When the battery cell experiences thermal runaway due to an internal short circuit or other cause and its temperature rises, it eventually releases high-temperature gas into the case 16.

The battery monitoring ECU 12 collects various battery information such as the output voltage, output current, temperature, and remaining charge (SOC: State of Charge) of the battery pack, and supplies the collected battery information to the higher-level ECU 14, which controls the vehicle, via a communication line (for example, CAN (Controller Area Network) communication).
In this embodiment, the battery monitoring ECU 12 has the function of detecting an abnormality in the battery pack 10 by detecting a break in the wiring unit body 20A, which will be described later.
When the higher-level ECU 14 receives detection information from the battery monitoring ECU 12 indicating an abnormality in the battery pack 10, it notifies the occupants that an abnormality has occurred in the battery pack 10, and prompts them to stop, for example, if the vehicle is in motion.

The pressure reducing valve 18A is installed in the case 16 and opens when the internal pressure of the case 16 rises to suppress the rise in internal pressure.
In this embodiment, the pressure reducing valve 18A is composed of a cylindrical portion 24 that constitutes the opening wall portion 22, a frame member 26, and a waterproof membrane 28, and the cylindrical portion 24 and the frame member 26 are made of metal or synthetic resin.
In this embodiment, the cylindrical portion 24 is cylindrical in shape, and the flange 2402 at the axial base of the cylindrical portion 24 is attached in a liquid-tight and airtight manner to mounting holes 1602 provided in the upper wall and side wall of the case 16.
The tip of the cylindrical portion 24, opposite the base, is open to the outside, and in this embodiment, the inside of the tip of the cylindrical portion 24 is the opening 30 of the case 16.

This opening 30 is sealed by a waterproof membrane 28 via a frame member 26.
The frame member 26 comprises a cylindrical portion 2602 and an annular plate portion 2604 that protrudes radially inward from the tip of the cylindrical portion 2602.
As shown in Figures 1 and 2, the waterproof membrane 28 has a disc shape with an outer diameter approximately the same as the inner diameter of the cylindrical portion 2602, and its outer circumference is attached to the inner surface of the ring plate portion 2604 in a liquid-tight and airtight manner by an adhesive or the like.
The ring plate portion 2604 is in contact with the tip surface of the cylindrical portion 2602 via the waterproof membrane 28, and the inner circumferential surface of the cylindrical portion 2602 is attached to the outer circumferential surface of the tip of the cylindrical portion 24 in a liquid-tight and airtight manner, with the waterproof membrane 28 sealing the opening 30.
The waterproof membrane 28 is made of a membrane that has the function of preventing the passage of water as a liquid, and by providing such a waterproof membrane 28, it is possible to prevent water from entering the inside of the case 16 from the outside through the opening 30.
Furthermore, the waterproof membrane 28 may be formed of a breathable waterproof membrane that prevents the passage of water as a liquid but allows water vapor to pass through. Forming the waterproof membrane 28 of a breathable waterproof membrane is advantageous in protecting the battery pack and electrical components by allowing moisture generated inside the case 16 to escape to the outside and preventing condensation inside the case 16.
Furthermore, when thermal runaway occurs in the battery pack (battery cells), the high-temperature gas generated causes the internal pressure of the case 16 to rise. In this case, the waterproof membrane 28 bulges upward and ruptures, releasing the high-pressure gas inside the case 16 to the outside, thereby suppressing the rise in internal pressure of the case 16. In other words, the pressure reducing valve 18A is opened by the rupture of the waterproof membrane 28.

The wiring unit body 20A is provided from the case 16 to the pressure reducing valve 18A and is disconnected when the pressure reducing valve 18A is opened.
In this embodiment, the wiring unit body 20A is composed of a waterproof membrane wiring unit 32, a first lead wire 34, and a second lead wire 36.
The waterproof membrane wiring section 32 is formed on the inner surface 2802 of the waterproof membrane 28 facing the inside of the case 16.
In this embodiment, as shown in Figure 2, the waterproof membrane wiring section 32 is formed of a conductive thin film that extends linearly in a strip shape along the diametrical direction of the waterproof membrane 28. In other words, it is provided so as to pass through the central part of the waterproof membrane 28, and the waterproof membrane wiring section 32 is disconnected when the waterproof membrane 28 is ruptured.

The first lead wire 34 connects the signal detection input terminal Ts of the battery monitoring ECU 12, which is grounded via a detection resistor R, to one end of the waterproof membrane wiring section 32.
The second lead wire 36 connects the voltage output terminal Te, which outputs a predetermined DC voltage E, provided in the electrical equipment section, to the other end of the waterproof membrane wiring section 32.
Therefore, when the waterproof membrane wiring section 32 is not disconnected, a DC voltage E is applied to the signal detection input terminal Ts of the battery monitoring ECU 12 via the second lead wire 36, the waterproof membrane wiring section 32, and the first lead wire 34.
On the other hand, when the waterproof membrane wiring section 32 is disconnected, the signal detection input terminal Ts of the battery monitoring ECU 12 is not subjected to a DC voltage E and is grounded (0V).
Therefore, the battery monitoring ECU 12 can detect that a break has occurred in the wiring unit body 20A based on the change in the signal detection input terminal Ts from a predetermined DC voltage E to a grounded state.
In other words, the battery monitoring ECU 12 detects a break in the wiring unit 20A, which in turn detects that the waterproof membrane 28 has ruptured due to an increase in internal case pressure, or in other words, that the pressure reducing valve 18A has opened. This allows the ECU to detect the generation of high-pressure gas inside the case 16, and therefore detect an abnormality in the battery pack 10.

Next, the effects will be explained with reference to the flowchart in Figure 3.
First, some kind of abnormality occurs in the battery pack 10, causing thermal runaway in the battery pack (step S10).
As time passes, high-temperature gas is generated from the battery pack (step S12), and the internal pressure of the case increases (step S14).
Eventually, the pressure inside the case causes the pressure reducing valve 18A to open (in this embodiment, the waterproof membrane 28 is ruptured) (step S16).
As a result, when the wiring unit body 20A is disconnected (step S18), the battery monitoring ECU 12 detects the disconnection of the wiring unit body 20A (step S20).
Then, the battery monitoring ECU 12 supplies detection information of the battery pack 10 malfunction to the higher-level ECU 14 (step S22).
As a result, the higher-level ECU 14 notifies the occupants of the abnormality using a display device provided on the instrument panel inside the vehicle (step S24).
It goes without saying that the form of abnormality notification may include emitting a warning sound from a speaker, or it may be done by combining a display device and a speaker.

According to this embodiment, a wiring section body 20A is provided extending from the case 16 to the pressure reducing valve 18A, which is disconnected when the pressure reducing valve 18A opens. The battery monitoring ECU 12 connected to the wiring section body 20A detects the disconnection of the wiring section body 20A, thereby detecting an abnormality in the battery pack 10.
Therefore, since there is no need to install a pressure sensor to detect the internal pressure of the case, which was previously required, manufacturing costs can be reduced, and the battery monitoring ECU 12 has an advantage in reliably detecting the internal pressure of the battery pack 10 in the same way as when a pressure sensor is installed, by detecting a break in the wiring unit body 20A.

In this embodiment, the pressure reducing valve 18A is opened by the rupture of the waterproof membrane 28 that seals the opening 30 provided in the case 16, and the rupture of the waterproof membrane 28 causes the waterproof membrane wiring portion 32 formed on the inner surface 2802 of the waterproof membrane 28 to be disconnected.
Therefore, since the waterproof membrane wiring section 32 is reliably disconnected almost simultaneously with the rupture of the waterproof membrane 28, it is advantageous for the battery monitoring ECU 12 to reliably detect the internal pressure of the battery pack 10.
The waterproof membrane wiring section 32 may be provided on the outer surface or inside of the waterproof membrane 28, but as in this embodiment, providing it on the inner surface 2802 of the waterproof membrane 28 facing the inside of the case 16 allows for easy connection to the first lead wire 34 and the second lead wire 36, which is advantageous in reducing costs.

Furthermore, in this embodiment, the wiring section body 20A includes a portion formed of a conductive thin film, and more specifically, the waterproof membrane wiring section 32 is formed of a conductive thin film. Therefore, when the waterproof membrane 28 is damaged, the wiring section body 20A is more likely to break, which is advantageous for the battery monitoring ECU 12 to reliably detect the internal pressure of the battery pack 10.

(Second embodiment)
Next, a second embodiment will be described with reference to Figures 4 and 5.
In the following embodiments, parts and components similar to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted or simplified. The descriptions will focus on the parts that differ.
The second embodiment is a modification of the first embodiment.
In the pressure reducing valve 18B of the second embodiment, the waterproof membrane wiring section 32 constituting the wiring section body 20B is provided to pass through the central part of the waterproof membrane 28, similar to the first embodiment.
In the second embodiment, as shown in Figures 4 and 5, a connector 42 is interposed in the waterproof membrane wiring section 32, which is different from the first embodiment.
In other words, the waterproof membrane wiring section 32 is composed of a first waterproof membrane wiring section 38, a second waterproof membrane wiring section 40, and a connector 42 that connects the first and second waterproof membrane wiring sections 38 and 40.
The base end of the first waterproof membrane wiring section 38 is connected to the first lead wire 34, and the base end of the second waterproof membrane wiring section 40 is connected to the second lead wire 36.
The connector 42 consists of a first connector member 4202 connected to the tip of the first waterproof membrane wiring section 38, and a second connector member 4204 connected to the tip of the second waterproof membrane wiring section 40 and detachable from the first connector member 4202. The first connector member 4202 and the second connector member 4204 are arranged in a connected state.
Then, due to the increase in internal case pressure, the waterproof membrane 28 bulges upward and ruptures, releasing the connection of the connector 42. In other words, the connection between the first connector member 4202 and the second connector member 4204 is released, causing the wiring unit body 20B to break.

According to the second embodiment, not only are the same effects as in the first embodiment achieved, but the connection of the connector 42 is easily released when the waterproof membrane 28 is ruptured due to an increase in internal case pressure. Therefore, when the waterproof membrane 28 is ruptured, the wiring unit body 20B is more likely to break, which is more advantageous for the battery monitoring ECU 12 to reliably detect the internal pressure of the battery pack 10.

(Third embodiment)
Next, a third embodiment will be described with reference to Figures 6 and 7.
The third embodiment is a modification of the second embodiment.
As shown in Figure 7, in the pressure reducing valve 18C of the third embodiment, the waterproof membrane wiring section 32 constituting the wiring section body 20B is formed of a conductive thin film and consists of a wiring section 44 extending from the edge to the center of the waterproof membrane 28.
As shown in Figure 6, the wiring section body 20B is configured to include a first wiring section 46 that extends from the end of the wiring section 44 located in the central part toward the case 16 side, away from the waterproof membrane 28.
The first wiring section 46 is connected to the voltage output terminal Te, similar to the second lead wire 36 in the first and second embodiments.
A connector 48 is interposed in the first wiring section 46, and therefore, the wiring section body 20C is configured to include the connector 48.
The connector 48 consists of a first connector member 4802 connected to the end of the wiring portion 44, and a second connector member 4804 that is removable from the first connector member 4802 and connected to the end of the first wiring portion 46. The first connector member 4802 and the second connector member 4804 are arranged in a connected state.
Then, due to the increase in internal case pressure, the waterproof membrane 28 bulges upward and ruptures, releasing the connection of the connector 48. In other words, the connection between the first connector member 4802 and the second connector member 4804 is released, causing the wiring unit body 20C to break.

According to the third embodiment, not only are the same effects as in the first embodiment achieved, but as in the second embodiment, when the waterproof membrane 28 is ruptured due to an increase in internal case pressure, the connection of the connector 48 is easily released. Therefore, when the waterproof membrane 28 is ruptured, the wiring unit body 20C is more likely to break, which is more advantageous for the battery monitoring ECU 12 to reliably detect the internal pressure of the battery pack 10.

(Fourth embodiment)
Next, a fourth embodiment will be described with reference to Figures 8 and 9.
In the fourth embodiment, the structure of the pressure reducing valve 18D differs from that of the first to third embodiments.
As shown in Figure 8, the pressure reducing valve 18D is composed of a cylindrical portion 50 that constitutes the opening wall portion 22, a cap member 52, a valve body 54, and a biasing member 56.
The cylindrical portion 50 is cylindrical in shape, and the flange 5002 at the axial base of the cylindrical portion 50 is attached in a liquid-tight and airtight manner to mounting holes 1602 provided in the upper wall and side wall of the case 16.
The tip of the cylindrical portion 50, opposite the base, is open to the outside, and in this embodiment, the inside of the tip of the cylindrical portion 50 is the opening 30 of the case 16.
The cap member 52 comprises a cylindrical wall portion 5202 and an upper wall 5204 that closes the upper end of the cylindrical wall portion 5202. The cylindrical wall portion 5202 has a plurality of windows 5206 formed at intervals in its circumferential direction to allow high-temperature gas to escape.
The inner circumferential surface of the ring plate portion 5208, which protrudes radially inward from the lower end of the cylindrical wall portion 5202, is attached to the outer circumferential surface of the cylindrical portion 50 in a liquid-tight and airtight manner.

The valve body 54 is disc-shaped and large enough to cover the upper end of the cylindrical portion 50 and close the opening 30. It is constantly biased in the direction of closing the opening 30 and moves upward above the opening 30 when the internal pressure of the case 16 increases, thereby opening the opening 30.
The biasing member 56 is composed of a coil spring provided between the upper wall 5204 and the valve body 54, and constantly biases the valve body 54 in a direction that closes the opening 30.

The wiring unit body 20D is composed of a valve body conductive portion 58, an opening conductive portion 60, a first lead wire 62, and a second lead wire 64.
As shown in Figure 9, the valve body conductive portion 58 is formed of a conductive thin film provided on the inner surface 5402 of the valve body 54 facing the inside of the case 16, and is formed in a strip shape extending along the diameter of the valve body 54 so as to pass through the center of the valve body 54.
As shown in Figure 8, the opening conductive portion 60 is provided on the upper end surface of the cylindrical portion 50 at locations 180 degrees apart in the circumferential direction of the cylindrical portion 50, and is composed of an opening first conductive portion 6002 and an opening second conductive portion 6004 connected to the battery monitoring ECU 12, each of which is formed of a conductive thin film.
More specifically, the first conductive opening 6002 is connected to the signal detection input terminal Ts of the battery monitoring ECU 12 via the first lead wire 62, and the second conductive opening 6004 is connected to the voltage output terminal Te via the second lead wire 64.

The pressure reducing valve 18D is assembled by aligning the valve body conductive portion 58 with the opening first conductive portion 6002 and the opening second conductive portion 6004 so that the valve body conductive portion 58 is connected to the opening first conductive portion 6002 and the opening second conductive portion 6004 when the valve body 54 is closing the opening 30, and the rotation of the valve body 54 is prevented by a rotation prevention mechanism (not shown). Various conventionally known structures can be used as the rotation prevention mechanism, for example, consisting of a pin protruding from the outer circumference of the valve body 54 and a groove provided on the inner surface of the cylindrical wall portion 5202 of the cap member 52 that supports the pin so as to be movable up and down.

As shown in Figure 8, with the valve body 54 closing the opening 30, the valve body conductive portion 58 and the opening conductive portion 60 are connected, causing the wiring unit body 20D to be in a conductive state (non-disconnected state), and a DC voltage E is applied to the signal detection input terminal Ts of the battery monitoring ECU 12 via the second lead wire 64, the second opening conductive portion 6004, the valve body conductive portion 58, the first opening conductive portion 6002, and the first lead wire 62.

On the other hand, as the internal pressure of the case rises, the valve body 54 moves upward and opens the opening 30, allowing the high-pressure gas inside the case 16 to be released to the outside of the case 16 through the window 5206, thereby suppressing the rise in internal pressure of the case 16. In other words, the opening of the pressure reducing valve 18D is achieved by the movement of the valve body 54.
As the internal pressure of the case increases, the valve body 54 moves upward, opening the opening 30. This disconnects the valve body conductive portion 58 from the opening's first conductive portion 6002 and opening's second conductive portion 6004, causing the wiring unit body 20D to become disconnected. Consequently, the signal detection input terminal Ts of the battery monitoring ECU 12 is grounded and no DC voltage E is applied to it.

Therefore, the battery monitoring ECU 12 can detect that a break has occurred in the wiring unit body 20D based on the change in the signal detection input terminal Ts from a predetermined DC voltage E to a grounded state.
In other words, the battery monitoring ECU 12 detects a break in the wiring unit 20D, which in turn detects that the waterproof membrane 28 inside the case 16 has ruptured when the internal pressure of the case rises, or in other words, that the pressure reducing valve 18D has opened. This allows the ECU to detect the generation of high-pressure gas inside the case 16 and detect an abnormality in the battery pack 10.

Furthermore, even when the internal pressure of the case is not rising, if the vehicle body vibrates significantly while driving, and a load is applied to the valve body 54, the valve body 54 will open and close against the biasing force of the biasing member 56, causing intermittent disconnections in the wiring unit body 20D, which may lead to the battery monitoring ECU 12 falsely detecting an abnormality in the battery pack 10.
In this case, for example, the battery monitoring ECU 12 can be configured to measure the disconnection time Td of the wiring unit body 20D, and if the disconnection time Td < predetermined time T0, the battery monitoring ECU 12 can determine that "no disconnection occurred," and if the disconnection time Td ≥ predetermined time T0, it can determine that "a disconnection occurred," thereby preventing false detections by the battery monitoring ECU 12.

According to the fourth embodiment, not only are the same effects as in the first embodiment achieved, but when the valve body 54 opens the opening 30 due to an increase in internal case pressure, the connection between the valve body conductive portion 58 and the opening conductive portion 60 is easily and reliably released, so the wiring portion body 20D is easily and reliably disconnected, which is advantageous for the battery monitoring ECU 12 to reliably detect the internal pressure of the battery pack 10.
Furthermore, the wiring section body 20D is composed of a portion formed of a conductive thin film, and in detail, the valve body conductive portion 58 and the opening conductive portion 60 are formed of a conductive thin film. Therefore, when the valve body 54 closes the opening 30, the valve body conductive portion 58 and the opening conductive portion 60 come into surface contact, ensuring electrical conductivity between them.
Therefore, even if there is a slight misalignment between the valve body conductive portion 58 and the opening conductive portion 60 while the valve body 54 is closing the opening 30, the wiring unit body 20D will not be disconnected, which is advantageous in preventing the battery monitoring ECU 12 from mistakenly detecting that the wiring unit body 20D has been disconnected.

Next, a modified example of the valve body conduction portion 58 of the fourth embodiment will be described with reference to Figures 10 and 11.
The valve body conductive portion 58 shown in Figure 10 is formed around the entire circumference of the outer periphery of the inner surface 5402 of the valve body 54, and more specifically, it is formed in an annular shape around the entire circumference of the outer periphery of the valve body 54.
The valve body conductive portion 58 shown in Figure 11 is formed around the entire circumference of the outer periphery of the inner surface 5402 of the valve body 54, and more specifically, it is formed over the entire area of the inner surface 5402 of the valve body 54.
The opening conductive portion 60 is provided on the upper end surface of the cylindrical portion 50 at locations 180 degrees apart in the circumferential direction of the cylindrical portion 50, similar to Figure 9, and includes an opening first conductive portion 6002 and an opening second conductive portion 6004, respectively, which are connected to the battery monitoring ECU 12.

Of course, these modifications also produce the same effects as the fourth embodiment. Moreover, according to each modification, regardless of the relative rotational position of the valve body 54 and the opening 30 around the axis, if the valve body 54 closes the opening 30, the valve body conductive portion 58 and the opening first conductive portion 6002 and the opening second conductive portion 6004 are reliably connected.
Therefore, when assembling the pressure reducing valve 18D, there is no need to align the rotational position of the valve body 54 and the opening 30 around the axis, in other words, there is no need to align the valve body conductive portion 58 with the opening first conductive portion 6002 and the opening second conductive portion 6004. Furthermore, a rotation prevention mechanism to prevent the rotation of the valve body 54 is also unnecessary. This simplifies the assembly of the pressure reducing valve 18D and is advantageous in reducing the cost of the battery pack 10.

Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to these examples. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these are naturally understood to fall within the technical scope of the present invention. Furthermore, the components of the above embodiments may be combined in any way without departing from the spirit of the invention.

This application is based on the Japanese Patent Application No. 2024-1756 filed on January 10, 2024, and its contents are incorporated herein by reference.

10 Battery pack 12 Battery monitoring ECU
14 Upper ECU
16 Case 1602 Mounting holes 18A, 18B, 18C, 18D Pressure reducing valve 20A, 20B, 20C, 20D Wiring section body 22 Wall section for opening 24 Cylinder section 2402 Flange 26 Frame member 2602 Cylinder section 2604 Ring plate section 28 Waterproof membrane 2802 Inner surface 30 Opening 32 Waterproof membrane wiring section 34 First lead wire 36 Second lead wire 38 First waterproof membrane wiring section 40 Second waterproof membrane wiring section 42 Connector 4202 First connector member 4204 Second connector member 44 Wiring section 46 First wiring section 48 Connector 4802 First connector member 4804 Second connector member 50 Cylinder section 5002 Flange 52 Cap member 5202 Cylinder wall section 5204 Upper wall 5206 Window section 5208 Ring plate section 54 Valve body 5402 Inner surface 56, biasing member 58, valve body conductive part 60, opening conductive part 6002, first opening conductive part 6004, second opening conductive part 62, first lead wire 64, second lead wire

Claims (7)

A battery pack comprising a case for housing a battery pack, and a pressure reducing valve provided in the case that opens when the internal pressure of the case rises to suppress the rise in the internal pressure,
A wiring section body is provided extending from the case to the pressure reducing valve and is disconnected when the pressure reducing valve is opened,
A battery monitoring ECU detects an abnormality in the battery pack by detecting a break in the wiring unit body,
Equipped with,
The pressure reducing valve is configured to include an opening provided in the case and a waterproof membrane that seals the opening.
The pressure reducing valve is opened by the rupture of the waterproof membrane.
The wiring section body is configured to include a waterproof membrane wiring section formed in the waterproof membrane, which is disconnected when the waterproof membrane is ruptured.
The waterproof membrane wiring section is provided so as to pass through the central part of the waterproof membrane.
The waterproof membrane wiring section is configured to include a connector interposed in the waterproof membrane wiring section,
The connection of the connector is released when the waterproof membrane is ruptured.
A battery pack characterized by the following features. A battery pack comprising a case for housing a battery pack, and a pressure reducing valve provided in the case that opens when the internal pressure of the case rises to suppress the rise in the internal pressure,
A wiring section body is provided extending from the case to the pressure reducing valve and is disconnected when the pressure reducing valve is opened,
A battery monitoring ECU detects an abnormality in the battery pack by detecting a break in the wiring unit body,
Equipped with,
The pressure reducing valve is configured to include an opening provided in the case and a waterproof membrane that seals the opening.
The pressure reducing valve is opened by the rupture of the waterproof membrane.
The wiring section body is configured to include a waterproof membrane wiring section formed in the waterproof membrane, which is disconnected when the waterproof membrane is ruptured.
The aforementioned waterproof membrane wiring section consists of a wiring portion extending from the edge to the central part of the waterproof membrane.
The wiring section body is configured to include a first wiring section that extends from the end of the wiring section located in the central part toward the case side, away from the waterproof membrane.
A connector is interposed in the first wiring section.
The connection of the connector is released when the waterproof membrane is ruptured.
A battery pack characterized by the following features. The pressure reducing valve is configured to include an opening wall portion provided in the case and forming an opening, and a valve body that is constantly biased in a direction that closes the opening and separates from the opening wall portion to open the opening when the internal pressure of the case rises.
The wiring section body comprises a valve body conductive portion provided on the valve body,
It comprises an opening conductive portion provided in the wall portion for the opening and connected to the battery monitoring ECU,
The valve body is connected to the opening while the valve body is closing the opening.
The connection between the valve body conductive portion and the opening conductive portion is released when the valve body opens the opening.
The battery pack according to claim 1, characterized in that it is as described above. The pressure reducing valve is configured to include an opening wall portion provided in the case and forming an opening, and a valve body that is constantly biased in a direction that closes the opening and separates from the opening wall portion to open the opening when the internal pressure of the case rises.
The wiring section body comprises a valve body conductive portion provided on the valve body,
It comprises an opening conductive portion provided in the wall portion for the opening and connected to the battery monitoring ECU,
The valve body is connected to the opening while the valve body is closing the opening.
The connection between the valve body conductive portion and the opening conductive portion is released when the valve body opens the opening.
The battery pack according to claim 2, characterized in that it is as described above. The valve body conductive portion is formed around the entire circumference of the outer periphery of the valve body.
The opening conductive portion is provided separately from each other in the circumferential direction of the opening wall portion and is connected to the battery monitoring ECU, and includes an opening first conductive portion and an opening second conductive portion, which are connected to the valve body conductive portion when the valve body is closing the opening.
The battery pack according to claim 3, characterized in that it is as described above. The valve body conductive portion is formed around the entire circumference of the outer periphery of the valve body.
The opening conductive portion is provided separately from each other in the circumferential direction of the opening wall portion and is connected to the battery monitoring ECU, and includes an opening first conductive portion and an opening second conductive portion, which are connected to the valve body conductive portion when the valve body is closing the opening.
The battery pack according to feature 4. At least a portion of the wiring section body is composed of a portion formed of a conductive thin film.
A battery pack according to any one of claims 1 to 6.