Patent Description:
At present, electric vehicle accidents frequently occur, which are mainly caused by spontaneous combustion of batteries. A battery includes a box body and a battery unit located inside the box body. As the energy density of the battery is gradually increased, the chemical system of the battery unit tends to have a higher energy density, and thus have a much larger volume. However, when the thermal failure occurs, the battery unit with a high energy density releases high-temperature heat flow. The high-temperature heat flow is prone to combustion when it comes into contact with air, and can further spread to adjacent battery units, thereby causing the whole battery pack to burn and thus putting the passengers and driver in danger. Prior art documents <CIT> and <CIT> are considered as relevant.

In view of above, the present disclosure provides a spray system for a battery pack and a battery pack, in order to solve problems of the burning of adjacent battery units and the personal safety of the passenger caused by the heat flow spreading during thermal failure.

In a first aspect of the present disclosure, a spray system for a battery pack is provided as recited in claim <NUM>.

Preferably, the driving device further includes a limiting component having a first working state and a second working state. In the first working state, the limiting component acts on the two driving plates to limit a distance between the two driving plates in such a manner that the elastic component is brought to a compressed state. In the second working state, the limiting component does not act on the two driving plates, and the distance between the two driving plates increases under the elastic force applied by the elastic component.

Preferably, the elastic component is one or more of a hydraulic spring, a constant force spring, or an elastic foam.

Preferably, two ends of the limiting component are respectively connected to the two driving plates, and the limiting component is provided with several breaking points, at each of which the limiting component is breakable; or the limiting component includes a glue material, through which a peripheral wall of each of the two driving plates and an inner wall of the liquid storage device are adhered together.

Preferably, a sliding seal structure is provided between a peripheral wall of each of the two driving plates and an inner wall of the liquid storage device.

Preferably, each of the two driving plates has a same distance from its respective one of the liquid outlets when the limiting component is in the first working state.

Preferably, the spray liquid in the liquid storage device and the spray pipeline is a fluorinated liquid.

In a second aspect of the present disclosure, a battery pack is provided. The battery pack includes a case having an inner cavity, a battery unit disposed in the inner cavity of the case and including a vent, and a spray system according to the first aspect. The spray pipeline of the spray system is provided in association with the vent.

In the present application, when a battery unit is thermally out of control and heat flow is discharged from its vent, under the effect of the heat flow, a spray pipeline can form an opening at a position corresponding to the vent under heating, such that spray liquid in the spray pipeline can be discharged through the opening, preventing the heat flow from spreading. In the meantime, after the spray liquid in the spray pipeline is discharged through the opening, the driving device can drive the spray liquid stored in the liquid storage device to flow into the spray pipeline and to be discharged through the opening of the spray pipeline, further preventing the heat flow from spreading.

Therefore, in the present spray system provided with the liquid storage device and the driving device, not only the spray liquid in the spray pipeline but also the spray liquid in the liquid storage device can be discharged to achieve spray. In this way, the spray effect is improved, and heat flow generated when one battery unit is thermally out of control is prevented from spreading to adjacent battery units, thereby improving the safety of the battery pack.

In order to more clearly illustrate technical solutions of embodiments of the present disclosure, the accompanying drawings used in the embodiments are briefly described below. The drawings described below are merely a part of the embodiments of the present disclosure. Based on these drawings, those skilled in the art can obtain other drawings without any creative effort.

In order to better understand technical solutions of the present disclosure, the embodiments of the present disclosure are described in details with reference to the drawings.

It should be clear that the described embodiments are merely part of the embodiments of the present disclosure rather than all of the embodiments.

The terms used in the embodiments of the present disclosure are merely for the purpose of describing specific embodiments, rather than limiting the present disclosure. The singular form "a", "an", "the" and "said" used in the embodiments and claims shall be interpreted as also including the plural form, unless indicated otherwise in the context.

It should be understood that, the term "and/or" is used in the present disclosure merely to describe relations between associated objects, and thus includes three types of relations. That is, A and/or B can represents: (a) A exists alone; (b) A and B exist at the same time; or (c) B exists alone. In addition, the character "/" generally indicates "or".

It should be understood that, the term such as "upper", "lower", "left", "right" and the like are used to indicate positions shown in the drawing, instead of being construed as limitations of the embodiment of the present disclosure. In addition, when an element is described as being "on" or "under" another element in the context, it should be understood that the element can be directly or via an intermediate element located "on" or "under" another element.

When battery units in the battery pack are thermally out of control, the battery pack is likely to be burned, which may put the vehicle and the passengers in danger. In the present disclosure, the safety of the battery pack is improved mainly by providing the battery pack with an additional spray system.

<FIG> is a structural schematic diagram of a battery pack according to an embodiment of the present disclosure; <FIG> is a partially enlarged view of Portion I of <FIG>; <FIG> is a structural schematic diagram of a spray system in <FIG>; <FIG> is a structural schematic diagram of a liquid storage device in <FIG>; <FIG> is a perspective view of <FIG>; <FIG> is an exploded view of <FIG>; <FIG> is a structural schematic diagram of a driving device in <FIG> when a limiting component is in a second working state; and <FIG> is a structural schematic diagram of a tank body and a cover body in <FIG>.

The present disclosure provides a battery pack as shown in <FIG>. The battery pack includes a case (not shown) having an inner cavity, one or more battery units <NUM> disposed in the inner cavity of the case. In case of a plurality of battery units <NUM>, they are arranged in a predetermined pattern and placed in the inner cavity of the case.

As shown in <FIG>, in the battery pack, the battery unit <NUM> is provided with a vent <NUM>. When the battery unit <NUM> is thermally out of control, a heat flow of high temperature and high pressure is generated inside the battery unit <NUM>, and the vent <NUM> is used to discharge the heat flow, so as to reduce the risk of burning and explosion of the battery unit <NUM>. Once the heat flow is discharged from the vent <NUM>, the high-temperature heat flow may cause combustion of adjacent battery units <NUM>. In order to reduce the risk of burning the adjacent units <NUM> when a certain battery unit <NUM> is out of control, a spray system <NUM> is provided in the battery pack of the present disclosure to reduce spreading of the heat flow and improve safety of the battery pack.

Specifically, as shown in <FIG> and <FIG>, the spray system <NUM> includes a spray pipeline <NUM> which is disposed corresponding to the vent <NUM> of the battery unit <NUM>. That is, the spray pipeline <NUM> passes through each battery unit <NUM> and located directly above the vent <NUM> of each battery unit <NUM>. The spray pipeline is configured to circulate a spray liquid and to form an opening for releasing the spray liquid when the spray pipeline <NUM> is heated. Meanwhile, as shown in <FIG>, the spray system <NUM> further includes a liquid storage device <NUM>, which communicates with the spray pipeline <NUM> and is used for storing the spray liquid. The spray system <NUM> further includes a driving device <NUM> configured to drive the spray liquid in the liquid storage device <NUM> to flow into the spray pipeline <NUM>.

According to the present disclosure, when the battery unit <NUM> is thermally out of control and the heat flow is discharged from the vent <NUM> of the battery unit <NUM>, the spray pipeline <NUM> is heated by the heat flow and thus forms an opening at a position corresponding to the vent <NUM>. Then the spray liquid in the spray pipeline <NUM> is discharged through the opening to prevent the heat flow from spreading. At the same time, after the spray liquid in the spray pipeline <NUM> is discharged through the opening, the spray liquid in the liquid storage device <NUM> can enter the spray pipeline <NUM> under the effect of the driving device <NUM>, and further be discharged through the opening of the spray pipeline <NUM>, thereby further preventing the heat flow from spreading.

In the spray system <NUM> provided with the liquid storage device <NUM> and the driving device <NUM>, not only the spray liquid in the spray pipeline <NUM> but also the spray liquid stored in the liquid storage device <NUM> can be sprayed, which greatly improves the effect of spraying. In this way, the risk of heat flow spreading when the battery unit <NUM> is thermally out of control can be lowered, and the safety of the battery pack can be improved.

When the spray pipeline <NUM> is subjected to the heat flow and partially cracks or totally breaks at the impacted position, no matter how the spray pipeline <NUM> is broken, the discharge of the spray liquid can be achieved as long as the opening is formed. Further, when the spray pipeline <NUM> is subjected to a heat flow at a temperature of <NUM> or higher (for example, <NUM>), the spray pipeline <NUM> can form the opening at a heated position. When the battery unit <NUM> of the battery pack is thermally out of control, if the heat flow ejected from the vent <NUM> of the battery unit <NUM> is at the temperature of <NUM> or higher, the spray pipeline <NUM> can form the opening.

Further, in the first embodiment as shown in <FIG>, the liquid storage device <NUM> has two liquid outlets <NUM> communicating with two ends of the spray pipeline <NUM>. In another embodiment, the spray system <NUM> includes two liquid storage devices <NUM> each having liquid outlet <NUM>, and the liquid outlets <NUM> of the two liquid storage devices <NUM> communicate with two ends of the spray pipeline <NUM>, respectively.

In the present embodiment, when a certain battery unit <NUM> in the battery pack is thermally out of control and discharges the heat flow, an opening is formed in the spray pipeline <NUM> corresponding to the vent <NUM> of this battery unit <NUM> under the heat flow. When both ends of the spray pipeline <NUM> communicate with one or more liquid storage devices <NUM>, a closed loop is formed by the spray pipeline <NUM> and the one or more liquid storage devices <NUM>. That is, the spray liquid that enters the spray pipeline <NUM> from both ends of the spray pipeline <NUM> can be discharged through the opening, thereby further increasing a discharging flow amount of the spray liquid. In this way, the spray liquid can be quickly discharged when an opening is formed at any position of the spray pipeline <NUM>, thereby improving the response speed.

In the embodiment as shown in <FIG>, when the spray system <NUM> includes one liquid storage device <NUM> and the liquid storage device <NUM> has two liquid outlets <NUM>, the two liquid outlets <NUM> are disposed at both ends of the liquid storage device <NUM> in an axial direction. In the meantime, as shown in <FIG>, the driving device <NUM> is disposed in the inner cavity of the liquid storage device <NUM>, and the driving device <NUM> includes two driving plates <NUM>, which are disposed along the axial direction and movable towards the corresponding liquid outlet <NUM>, respectively.

In the embodiment as shown in <FIG>, the two driving plates <NUM> of the driving device <NUM> are disposed in the inner cavity of the liquid storage device <NUM>, and respectively move towards the corresponding liquid outlet <NUM> when the liquid storage device <NUM> is filled with the spray liquid. For example, in <FIG>, the left driving plate <NUM> moves to the left side and the right driving plate <NUM> moves to the right side. During the movement of the driving plates <NUM>, the spray liquid in the liquid storage device <NUM> can be pushed into the spray pipeline <NUM> from the corresponding liquid outlet <NUM>. In other words, the driving plate <NUM> applies thrust to the spray liquid in the liquid storage device <NUM> and the spray pipeline <NUM>, so as to drive the spray liquid to be discharged through the spray pipeline <NUM>, thereby achieving spraying.

Further, in order to enable the two driving plates <NUM> to move towards the corresponding liquid outlet <NUM>, as shown in <FIG>, the driving device <NUM> further includes an elastic component <NUM> and a limiting component <NUM>. Two ends of the elastic component <NUM> are connected to the two driving plates <NUM>, respectively. At the same time, the limiting component <NUM> has a first working state and a second working state. In the first working state, the limiting component <NUM> can limit a distance between the two driving plates <NUM> in such a manner that the elastic component <NUM> is in a compressed state, i.e., the limiting component <NUM> acts on the two driving plates <NUM> such that the two driving plates <NUM> are close to each other and thus compress the elastic component <NUM>. In the second working state, the limiting component <NUM> can release restriction on the distance between the two driving plates <NUM>, i.e., the limiting component <NUM> releases the restriction on the driving plates <NUM> and thus the elastic component <NUM>, such that the elastic component <NUM> can be restored to an initial state (elongation).

In the present disclosure, the driving device <NUM> includes two driving plates <NUM>, the elastic component <NUM> and the limiting component <NUM>. In the initial state (i.e., the limiting component <NUM> is in the first working state), the elastic component <NUM> between the two driving plates <NUM> is in the compressed state, such that the driving device <NUM> stores the elastic potential energy. When no opening is formed in the spray pipeline <NUM> (the battery unit <NUM> is not thermally out of control yet), in the inner cavity of the liquid storage device <NUM>, the elastic force of the elastic component <NUM> in the driving device <NUM> is equal to a sum of a hydraulic pressure of the spray liquid on the driving plates <NUM> and a pulling force of the limiting component <NUM> on the driving plates <NUM>, so that the elastic component <NUM> can be maintained in the compressed state. When an opening is formed in the spray pipeline <NUM> and the spray liquid is discharged through the opening, the hydraulic pressure in the liquid storage device <NUM> is reduced such that the balance is broken. Then, under a restoring force of the elastic component <NUM>, the restriction of the limiting component <NUM> (which is in the second working state) is overcame, and the elastic potential energy of the elastic component <NUM> is converted into a kinetic energy for the driving plates <NUM>, so that the two driving plates <NUM> are driven to move towards the liquid outlets <NUM> to drive the spray liquid to be discharged.

Therefore, there is need to provide the spray system <NUM> according to the present disclosure with a monitoring device and a control device. That is, the spray system <NUM> does not need to be provided with a sensor. The spraying can be achieved with the relationship between the components of the spray system <NUM>, and the response speed is fast and the structure is simple.

In the present disclosure, the limiting component <NUM> functions to limit the distance between the two driving plates <NUM>. Thus, in the first embodiment, the limiting component <NUM> can include a glue material disposed between a peripheral wall of the driving plates <NUM> and an inner wall of the liquid storage device <NUM>, so that the driving plates <NUM> and the liquid storage device <NUM> can be adhered together. At this moment, the limiting component <NUM> is in the first working state, as shown in <FIG>. When the opening is formed in the spray pipeline <NUM>, the adhesion effect generated by the glue material between the driving plates <NUM> and the liquid storage device <NUM> is removed under the effect of the elastic component <NUM>, and the limiting component <NUM> is in the second working state, as shown in <FIG>.

In an embodiment, the glue material can be glue or adhesive tape. The adhesive force of the glue material exerted on the driving plates <NUM> and the liquid storage device <NUM> can be changed by setting parameters such as an amount of glue or an area of the adhesive tape. In this way, after the opening is formed in the spray pipeline <NUM>, the glue material will lose the effect after a predetermined period (for example, the glue material will be invalid in <NUM> minutes after the opening is formed in the spray pipeline <NUM>).

In the second embodiment as shown in <FIG>, the limiting component <NUM> can also be a strip structure connected between the two driving plates <NUM>, and the limiting component <NUM> is provided with several breaking points 133a. When no opening is formed in the spray pipeline <NUM>, the limiting component <NUM> is not broken yet at the breaking points 133a, and the limiting component <NUM> is in the first working state. When an opening is formed in the spray pipeline <NUM>, the driving plates <NUM> has a tendency to move in an opposite direction under the effect of the elastic component <NUM>, so that the limiting component <NUM> is broken at the break points 133a, and the limiting component <NUM> is in the second working state.

In another aspect, the elastic component <NUM> can be a spring, an elastic foam or the like, as long as it can be elastically deformed. Further, in the embodiment shown in <FIG>, the elastic component <NUM> is preferably a constant force spring, which has a nearly constant elastic force with a change of the expansion and contraction amount. Therefore, in the driving device <NUM>, the elastic component <NUM> can provide a constant elastic force rather than a gradually reduced elastic force during elongation, thereby further promoting the spray liquid to enter spray pipeline <NUM> from the liquid storage device <NUM>.

As shown in <FIG>, the driving plates <NUM> can be disposed in the liquid storage device <NUM> in such way that when the opening is formed in the spray pipeline <NUM>, the driving plates <NUM> can move axially along the inner wall of the liquid storage device <NUM>, and when no opening is formed in the spray pipeline <NUM> yet, the spray liquid cannot flow or flow with a low flow rate between the peripheral wall of the driving plates <NUM> and the inner wall of the liquid storage device <NUM>, such that the liquid pressure of the spray liquid is affected to a small extent. That is, when no opening is formed in the spray pipeline <NUM> yet, there is no spray liquid or only a small amount of spray liquid is present between the two driving plates <NUM>.

In a specific embodiment, a dynamic sealing structure (for example, a packing sealing or the like) can be disposed between the driving plates <NUM> and the liquid storage device <NUM>, so that the driving plates <NUM> can move with respect to the inner wall of the liquid storage device <NUM> and the dynamic sealing structure has the sealing effect to prevent the spray liquid from entering the space between the two driving plates <NUM>.

In another aspect, as shown in <FIG>, when no opening is formed in the spray pipeline <NUM> yet and the limiting component <NUM> is still in the first working state, the distances between the two driving plates <NUM> and the corresponding liquid outlets <NUM> are equal, i.e., the driving device <NUM> is at the middle position of the liquid storage device <NUM> along the axial direction. In this regard, the hydraulic pressures received by the two driving plates <NUM> are substantially equal, which is conducive to maintaining the balance of the driving device <NUM> when no opening is formed in the spray pipeline <NUM> and also enables the spray liquid to be discharged from the two liquid outlets <NUM> when the opening is formed in the spray pipeline <NUM>.

In the above embodiment, the liquid storage device <NUM> has two oppositely disposed liquid outlets <NUM>, which are connected to the spray pipeline <NUM> to form a closed loop. In such an embodiment, it is merely required to provide one liquid storage device <NUM> and one driving device <NUM> in order to discharge the spray liquid from the two liquid outlets <NUM> of the liquid storage device <NUM>. Such configuration has advantages of a simple structure, space saving, low cost, and uneasy failure.

In this embodiment, the liquid storage device <NUM> may be embodied as a liquid storage tank. As shown in <FIG>, the liquid storage device includes a tank body <NUM> and a cover body <NUM>, and the tank body <NUM> and the cover body <NUM> can be connected via a threaded connection, a clamping connection or the like. The liquid storage device <NUM> is required to satisfy a high sealing performance and can withstand a relatively high pressure. In an embodiment, it can be made of a metal material having high pressure resistance such as iron or stainless steel, and can also be made of a plastic material such as polypropylene (PP). The liquid storage device <NUM>, when being made of stainless steel, can be formed as an integral structure with the spray pipeline <NUM>, or can be connected with the spray pipeline <NUM> by welding. When the liquid storage device <NUM> is made of a plastic material such as PP, the liquid storage device <NUM> and the spray pipeline <NUM> can be connected by a push-in fitting.

The spray system <NUM> as shown in <FIG> may be installed according to the following procedures: Firstly, the spray pipeline <NUM> is installed and then welded with the liquid storage device <NUM>, so as to ensure a communication and a fluent flowing pathway between the spray pipeline <NUM> and the liquid outlets <NUM> of the liquid storage device <NUM>; secondly, one end of the spray pipeline <NUM> is sealed with a cover or tape, and the spray liquid is filled into the liquid storage device <NUM> through the other end until reaching a level at a scale mark in the liquid storage device <NUM> (the scale mark is at such a position that the driving device <NUM> can be located at the middle position of the liquid storage device <NUM>), then the driving device <NUM> is placed into the liquid storage device <NUM>, and the limiting component <NUM> is placed in the first working state (the elastic component <NUM> is in the compressed state); thirdly, the cover body <NUM> of the liquid storage device <NUM> having thread is tightened with the tank body <NUM>, and the spray liquid is further added through the spray pipeline <NUM> until the entire system is filled with the spray liquid; and fourthly, the other end of the spray pipeline <NUM> and the liquid storage device <NUM> are fixedly sealed by welding to complete the overall sealing.

In a second embodiment, the liquid storage device <NUM> is merely provided with one liquid outlet. The liquid storage device <NUM> includes a first end and a second end opposite to the first end. The first and second ends are disposed along an axial direction. The second end is closed, and the first end is provided with a liquid outlet <NUM> communicating with the spray pipeline <NUM>. In this embodiment, the driving device <NUM> is disposed in the inner cavity of the liquid storage device <NUM>, and the driving device <NUM> includes a driving plate <NUM>, an elastic component <NUM> and a limiting component <NUM>. Two ends of the elastic component <NUM> are respectively connected to the driving plate <NUM> and the second end. The limiting component <NUM> has a first working state and a second working state. In the first working state, the limiting component <NUM> can limit a distance between the driving plate <NUM> and the second end, so as to bring the elastic component <NUM> in the compressed state. In the second working state, the limiting component <NUM> can release the restriction on the driving plate <NUM>, such that the driving plate <NUM> can move towards the liquid outlet <NUM>.

In the spray system <NUM> according to the present embodiment, the liquid storage device <NUM> merely has one liquid outlet <NUM>, and the spray liquid can be discharged only through this liquid outlet <NUM>. In order to improve the spraying effect, both ends of the spray pipeline <NUM> are respectively connected to the liquid storage device <NUM> as described in the second embodiment, i.e., the spray system <NUM> includes two liquid storage devices <NUM> and two driving devices <NUM>.

In another aspect, in the above embodiment, the spray liquid in the liquid storage device <NUM> and the spray pipeline <NUM> is a fluorinated liquid. The fluorinated liquid, after being sprayed from the spray pipeline <NUM>, can chemically react with the heat flow of the battery unit <NUM>, thereby absorbing heat and preventing heat from spreading.

In addition, the embodiments of the present disclosure further provide a spray system <NUM> as shown in <FIG>. The spray system includes a spray pipeline <NUM> configured to circulate a spray liquid and form an opening under heating for use in discharging of the spray liquid; a liquid storage device <NUM> communicating with the spray pipeline <NUM> and configured to store the spray liquid; and a driving device <NUM> configured to drive the spray liquid in the liquid storage device <NUM> to flow into the spray pipeline <NUM>.

The spray system <NUM> can be applied in the battery pack to prevent the heat flow from spreading when the battery unit <NUM> in the battery pack is thermally out of control, thereby extinguishing fire. The spray system <NUM> can also be used in other occasions where fire extinguishing is required.

Claim 1:
A spray system (<NUM>) for a battery pack, characterized in comprising:
a spray pipeline (<NUM>) configured to circulate a spray liquid and forming an opening when being heated;
a liquid storage device (<NUM>) comprising two liquid outlets (<NUM>) that are located at two ends of the liquid storage device (<NUM>) along an axial direction thereof and communicate with two ends of the spray pipeline (<NUM>), respectively; and
a driving device (<NUM>) disposed in an inner cavity of the liquid storage device (<NUM>) and comprising a driving component and an elastic component (<NUM>) connected to the driving component, wherein the driving component comprises two driving plates (<NUM>) disposed along the axial direction, the two driving plates (<NUM>) being respectively connected to two ends of the elastic component (<NUM>) and each movable towards a respective one of the two liquid outlets (<NUM>),
wherein the two driving plates (<NUM>), under an elastic force applied by the elastic component (<NUM>), drives the spray liquid in the liquid storage device (<NUM>) to flow into the spray pipeline (<NUM>).