Single-cell battery, battery module, power battery, and electric vehicle

The present disclosure discloses a single-cell battery, a battery module, a power battery, and an electric vehicle. The single-cell battery includes a case, a battery cell accommodated in the case, an electrode terminal electrically connected to the battery cell, and a cover plate for sealing the case. The electrode terminal is disposed on the cover plate. The electrode terminal includes a battery post passing through the cover plate and electrically connected to the battery cell with an internal guide member. The single-cell battery further includes a current interruption device mounted on the battery post. The current interruption device includes a flipping member in communication with gas inside the case. The flipping member is connected to an outer end surface of the battery post with a connection point. The connection point is configured to be disconnected under action of air pressure.

TECHNICAL FIELD

The present disclosure relates to the field of batteries, and in particular, to a single-cell battery, a battery module including the single-cell battery, a power battery including the battery module, and an electric vehicle including the power battery.

BACKGROUND

As energy storage units, batteries play an important role in various industries. For example, power batteries are widely applied in fields such as new energy vehicles. In a battery pack of a power battery, multiple single-cell batteries may be connected in series or in parallel to form a battery module, to implement a charge/discharge operation. The power battery usually uses a battery management system (BMS) to monitor a voltage change and a current change and calculate a state of charge in the charge/discharge process. However, a voltage sampling failure may lead to overcharging of the battery. Particularly, in a ternary system, there is a danger of battery burning or explosion if the overcharging reaches a certain amount.

In the existing technical solution, during monitoring of a battery voltage and current, a current integration method and an open circuit voltage method are used to calculate a battery level, to control battery charge/discharge management. However, there are disadvantages. For example, because of a battery voltage sampling failure, a battery current sampling failure, or a software failure, a battery is recharged for a long time and out of control. Particularly, in a case of recharging by using a charging pile, overcharging cannot be controlled if the charging pile fails to communicate with a battery manager, and when the overcharging reaches a certain amount, battery swelling and even explosions or fires are caused.

Therefore, it is of positive significance to provide a current interrupt technology for proactively and forcibly interrupting a current.

SUMMARY

An objective of the present disclosure is to provide a single-cell battery. The single-cell battery has an ingenious structure and can forcibly interrupt a current when in danger, thereby preventing a danger such as a battery explosion from occurring.

The objective of the present disclosure is to further provide a battery module using the single-cell battery, a power battery using the battery module, and an electric vehicle using the power battery.

To achieve the foregoing objectives, the present disclosure provides a single-cell battery. The single-cell battery includes a case, a battery cell accommodated in the case, an electrode terminal electrically connected to the battery cell, and a cover plate for sealing the case. The electrode terminal is disposed on the cover plate. The electrode terminal includes a battery post passing through the cover plate and electrically connected to the battery cell by using an internal guide member. The single-cell battery further includes a current interruption device mounted on the battery post. The current interruption device has a flipping member in communication with gas inside the case. The flipping member is connected to an outer end surface of the battery post by using a connection point. The connection point can be disconnected under action of air pressure.

Preferably, the flipping member is connected to the battery post by using a single welding spot.

Preferably, the battery post includes an air-guide hole in communication with the inner part of the case.

Preferably, the flipping member includes a notch. The notch is disposed surrounding the connection point.

Preferably, the connection point can be pulled apart under action of first air pressure inside the case, the notch can be pulled apart under action of second air pressure, and the second air pressure is greater than the first air pressure.

Preferably, the flipping member is covered by a covering cap, and the covering cap includes an air hole.

Preferably, a first ceramic ring is connected between the battery post and the cover plate.

Preferably, a second ceramic ring is tightly connected between the battery post and an outer periphery of the flipping member.

Preferably, the battery post has an annular boss surrounding the connection point. The first ceramic ring is tightly accommodated in a rear concave portion of the annular boss. The first ceramic ring is tightly connected to the cover plate. A radial outer side of the annular boss tightly supports the second ceramic ring. The second ceramic ring tightly supports the outer periphery of the flipping member.

Preferably, the first ceramic ring is tightly connected to the cover plate by using a transition ring.

The present disclosure further provides a battery module. The battery module includes the single-cell battery according to the present disclosure.

The present disclosure further provides a power battery, including an inclusion body and a battery module disposed inside the inclusion body. The battery module is the battery module according to the present disclosure.

The present disclosure further provides an electric vehicle. The electric vehicle includes the power battery according to the present disclosure.

In the foregoing technical solution, a gas may be produced when the battery is in an emergency case. Therefore, as the air pressure increases, a flipping member can flip over under action of the air pressure, to disconnect from the battery post, thereby disconnecting the charge/discharge circuit of the power battery, and further avoiding a further increase in the battery air pressure and explosions.

Other features and advantages of the present disclosure are to be described in detail in the following part of detailed description.

DETAILED DESCRIPTION

The following describes in detail specific embodiments of the present disclosure with reference to the accompanying drawings. It should be understood that the specific embodiments herein are used merely for describing the present disclosure and are not intended to limit the present disclosure.

Unless otherwise specified, nouns of locations such as “up, down, left, and right” used in the present disclosure are generally defined based on figure plane directions of corresponding accompanying drawings, and “inside and outside” refers to an inner part and an outer part of a corresponding component.

The present disclosure provides technical solutions of a current interruption device, a single-cell battery, a battery module, a power battery, and an electric vehicle. The current interruption device is disposed inside the single-cell battery. Multiple single-cell batteries are connected in series or in parallel to form the battery module and may be placed inside a battery pack to form the power battery. Moreover, in addition to the field of power batteries, various technical solutions provided in the present disclosure may be further widely applied to other battery fields. Specifically, the present disclosure relates to single-cell batteries100,1100,2100,3100, and4100, and relates to current interruption devices200,1200,3200,4200, and an explosion relief valve2200. In addition, the present disclosure further relates to a charge/discharge protection system having the power battery. The following describes the embodiments in detail with reference to the accompanying drawings.

First, the present disclosure provides a battery module, including the multiple single-cell batteries100,1100,2100,3100, and4100. The single-cell battery may include a case, a battery cell accommodated in the case, electrode terminals101,1101,2101,3101, and4101electrically connected to the battery cell, and cover plates102,1102,2102,3102, and4102for sealing the case. The electrode terminal is disposed on the cover plate, to input and output currents. The single-cell battery includes the current interruption devices200,1200,3200, and4200or the explosion relief valve2200. The current interruption device or the explosion relief valve is electrically connected to the electrode terminal. Therefore, input and output of currents on the electrode terminal can be controlled under action of the current interruption device. That is, for the current interruption device or the explosion relief valve in the single-cell battery is normally connected to the battery cell. In this case, the electrode terminal can normally input and output currents, to complete a charge/discharge operation of the single-cell battery. However, in an emergency state, for example, when the battery is overcharged, the current interruption device or the explosion relief valve may stop the current input and output of the electrode terminal, to prevent the battery from being recharged at an excessive rate. Therefore, reliability of the current interruption device is crucial as an important safety measure. That is, the current interruption device needs to be capable of making a quick response. Moreover, the current interruption device or the explosion relief valve may alternatively be fixed relative to the cover plate. That is, the current interruption device or the explosion relief valve may be directly fixed to the cover plate, or may be fixed to any component connected to the cover plate or fixed relative to the cover plate. For example, the current interruption device or the explosion relief valve is mounted on the electrode terminal in the cover plate.

In the present disclosure, the current interruption device or the explosion relief valve each is a mechanical structure for sensing the air pressure. Specifically, the current interruption device is in communication with gas inside the case of the single-cell battery, and can interrupt, under action of the air pressure, a current passing through the current interruption device. Specifically, connections between internal components may be disconnected to stop current transmission, thereby stopping charging/discharging of the battery in a timely manner. A source of the air pressure used is: for example, when an emergency case such as overcharging of the battery occurs, a gas is produced inside the battery, then leading to an increase in the air pressure inside the case, or an exception occurs in the battery during use, causing an increase in the temperature of the battery and an increase in the air pressure inside the battery, thereby generating air pressure power for driving the current interruption device or the explosion relief valve.

FIG. 1toFIG. 12provide some embodiments. As shown inFIG. 3toFIG. 6,FIG. 8, andFIG. 10, the current interruption device200has a conductive member201and a flipping member202electrically connected to the conductive member201. The flipping member202and the conductive member201can be electrically disconnected from each other under action of air pressure. In the present disclosure, electrical disconnection may be implemented in different manners. A connection point between may be disconnected. For example, a welding spot between the conductive member and the flipping member is removed to implement the electrical disconnection. Alternatively, at least one of the conductive member and the flipping member is broken. For example, a weakening notch is made in a corresponding component to implement disconnection of a structure, thereby implementing the electrical disconnection. That is, an objective of stopping current transmission by disconnecting a mechanical structure under action of the air pressure is achieved in the present disclosure.

In this way, for example, when the battery is overcharged, a gap is produced inside the battery and then the air pressure increases. In this case, the flipping member202is disconnected from the conductive member201by performing a flipping action, so that a circuit between the electrode terminal101and the outside is disconnected, and charging of the battery is stopped, thereby avoiding a further increase in the air pressure inside the battery, and ensuring battery safety.

The electrode terminal101includes a battery post104electrically connected to the battery cell. For example, the battery post104is connected to the battery cell by using an internal guide member. The battery post104passes through the cover plate102to guide a current from the case. The current interruption device200is mounted on the battery post104. In this way, the air pressure inside the battery may be detected by using the battery post104, so that the sensitivity is high. Moreover, the current interruption device200does not need to be connected to the electrode terminal additionally, thereby facilitating processing.

In a field such as the field of power batteries, a high current needs to pass. Therefore, stability of a welded structure of the conductive member201and the flipping member202needs to be ensured, to prevent the high current from breaking the welded structure. In this way, in an embodiment, as shown inFIG. 5andFIG. 6, the flipping member202and the conductive member201are connected to each other by using a boss welded structure. The boss welded structure includes a boss203, a connection hole204accommodating the boss203, and an annular welding spot217located between the boss203and the connection hole204. Therefore, it can be ensured that the annular welding spot217is used to firmly weld the boss203accommodated in the connection hole204, and a passing area of the current can be increased to ensure passing of the high current. Specifically, the boss203is formed in the conductive member201, and the connection hole204is formed in the flipping member202. More specifically, the flipping member202is formed with a first sheet-like structure, the first sheet-like structure includes the connection hole204, the conductive member201is formed with a second sheet-like structure, and the second sheet-like structure includes the boss203. In another embodiment, alternatively, the boss203may be disposed on the flipping member202, and the connection hole204is disposed in the conductive member201. Moreover, in some embodiments, the flipping member202and the conductive member201may be alternatively welded together by using a laser penetration welding manner, or the like.

The flipping member and the conductive member may be electrically disconnected from each other by using a notch. That is, a weakening portion with strength less than that of a weakening portion in another region is provided in a corresponding part. In order that the conductive member and the flipping member are completely disconnected from each other, the notch is usually an annular structure surrounding a connection point between the conductive member and the flipping member, for example, the boss welded structure. In this way, electrical disconnection is implemented with disconnection of the conductive member or the flipping member. The notch may be formed in the flipping member or may formed in the conductive member. In an embodiment, the conductive member201includes a notch205. The notch205is surrounding a connection point for connecting to the flipping member202. That is, an annular notch is disposed in the conductive member201and surrounding the boss203. In this way, when the air pressure inside the battery increases, the notch205may be pulled apart under action of the air pressure, so that the part of the boss203surrounded by the notch205is separated from the conductive member201with the flipping member202, thereby implementing interruption of the current. In another implementation, alternatively, the notch may be formed in the flipping member202.

As shown inFIG. 7, to help pulling the notch205apart, preferably, the notch205is elliptical. In this way, under action of the air pressure, because of different contour curvature, stress is more easily concentrated in a region with a greater curvature and the received force is strong. In this way, such a region can be first torn, thereby increasing sensitivity in pulling the notch205apart. Further, in this embodiment, the boss203is circular, and a center of the elliptical notch205and a center of the boss203are staggered a long a direction of major axis of the ellipse. In this way, regions at two ends of the major axis of the ellipse may receive uneven force, so that the notch205is easily pulled apart at a local point, thereby improving sensitivity of the notch205.

Moreover, the flipping member202and the electrode terminal101may be coaxially disposed, and the conductive member201is obliquely disposed relative to an axial line of the electrode terminal101. In this way, a notch at a lower location may be first pulled apart, thereby increasing sensitivity in pulling the notch205apart. Further, when the notch205is elliptical, in a design, the major axis of the ellipse and the axial line of the conductive member are obliquely disposed. When the conductive member is mounted on the battery post, the conductive member and an axial line of the battery post are also obliquely disposed. In this way, a region with greater curvature on an end portion of the major axis is first and easily torn, thereby ensuring that the notch205can be normally pulled apart when needed, and ensuring normal operation of the current interruption device200.

Moreover, to further ensuring that the notch205is pulled apart, alternatively, as shown inFIG. 7, in a design, the notch205includes a weakening hole206. In this way, the notch205is easily pulled apart at a location of the weakening hole206. A size of the weakening hole206and a quantity of weakening holes206may be set according to an actual situation. Preferably, there are multiple weakening holes206disposed at intervals along the notch205. In addition to the effect of weakening, when the notch is designed in the conductive member201, the weakening hole206may be further used for air guiding, so that the gas inside the battery can apply the air pressure to the flipping member202by using the weakening hole206.

As shown inFIG. 3,FIG. 8, andFIG. 10, when the current interruption device200is mounted on the battery posts104,104′, and104″, the conductive member201is connected to outer end surfaces of the battery posts104,104′, and104″, and an outer periphery of the flipping member202is fixed relative to the cover plate102. In this way, under action of air pressure, the outer periphery of the flipping member202is used as a support point, and the notch205formed in the conductive member201can be pulled apart. Moreover, to enable the flipping member202to be under action of the air pressure, the outer periphery of the flipping member may be sealed, for example, may be tightly connected to the cover plate with welding, to that the internal air pressure can apply force to the flipping member to pull the notch205apart. Herein and in similar descriptions, an outer end or an inner end is defined relative to the case along an axial direction of the battery post, and the “inside and outside” relative to an annular member, for example, the outer periphery, is defined relative to a center of the annular member along the radial direction.

To ensure that the notch205in the conductive member201can still be pulled apart when the conductive member201and the battery post104′ are fixed, preferably, the outer end surface of the battery post104includes an accommodation hole218, and an outer periphery of the conductive member201is fixed to an inner wall of the accommodation hole. In this way, the conductive member201may be stably fixed at the annular periphery, while a region inside the notch205can be pulled apart under action of external force such as tensile force of the flipping member202or the direct pressure of the gas because the region inside the notch205is not connected to the battery post104.

In the present disclosure, the current interruption device may be in communication with gas inside the battery in multiple manners. The battery posts104and104′ are each provided with an air-guide duct communicating an inner part of the case and the current interruption device200. In this way, air pressure is applied to the current interruption device by directly using internal structures of the battery posts104and104′. Therefore, the structure is simpler.

In an embodiment shown inFIG. 8andFIG. 9, the air-guide duct includes two types of air-guide holes103. A first-type air-guide hole103is used to communicate the accommodation hole218and an inner part of the case, that is, directly apply pressure to the conductive member201to punch the notch205apart. That is, the air-guide duct includes the air-guide hole103for communicating the accommodation hole218and the inner part of the case. A second-type air-guide hole103is used to communicate the flipping member202and the inner part of the case, to apply pressure to the flipping member to pull the notch205apart. To improve stress distribution efficiency of the flipping member202, there are multiple such type of air-guide holes103surrounding the accommodation hole. Therefore, under joint action of the two types of air-guide holes103, sensitivity of the current interruption device can be improved.

Specifically, as shown inFIG. 8, the battery post104′ is fixedly connected to the cover plate102, so that the structure of the electrode terminal is stable. An outer end periphery the battery post104′ has a radial boss105, the radial boss105fixedly connected to the cover plate102, and the second-type air-guide hole103is formed in the radial boss105, so that gas flows to the flipping member202. The first-type air-guide holes103are formed inside the battery post104′ along an axial direction. That is, the air-guide hole103located in the radial boss105is used to apply pressure to the flipping member202, while the air-guide hole103below the accommodation hole218may directly apply pressure to the conductive member201. As shown inFIG. 9, in this embodiment of the present disclosure, the radial boss105of the battery post104′ and a body of the battery post are both provided with the air-guide hole103. The first-type air-guide holes103in the body of the battery post is in communication with the accommodation hole218in the end surface, and there are four first-type air-guide holes103which are disposed at equal intervals along a circumferential direction. In another embodiment, alternatively, there may be another quantity of first-type air-guide holes103. The quantity of first-type air-guide holes is not limited in the present disclosure.

As shown inFIG. 3,FIG. 8, andFIG. 10, to prevent the cover plate from being electrified, preferably, the battery posts104,104′, and104″ need to be insulated from the cover plate when fixedly connected to the cover plate. Therefore, the battery posts104,104′, and104″ are fixedly connected to ceramic rings207and207′ tightly connected to the cover plate102, for example, with ceramic brazing. This achieves higher reliability and weather resistance than insulation implemented by using plastics or rubber, and not only stable and tight connection of the current interruption device can be implemented, but also insulation between the battery posts and the cover plate can be implemented. Specifically, outer end peripheries of the battery posts104,104′, and104″ have the radial bosses105and105′, and inner edges of the ceramic rings207and207′ have radial supports208and208′ supporting and connected to the radial bosses105and105′. The radial bosses105and105′ are embedded in the ceramic rings207and207′ and are connected to the radial supports208and208′. That is, the radial supports208and208′ are relatively thin to form a staircase-type accommodation space in which the battery posts104,104′, and104″ are embedded.

In the embodiment shown inFIG. 11, different from the foregoing gas release manner in which the battery post includes the air-guide hole103, there are multiple radial bosses105′ and multiple radial supports208′ disposed at intervals along the circumferential direction. That is, there are multiple radial bosses105′ disposed at intervals along the circumferential direction, and there are multiple radial supports208′ disposed at intervals along the circumferential direction. In addition, the multiple radial bosses are in a one-to-one correspondence with the multiple radial supports. In this way, gas release may be implemented by using spacing between adjacent radial bosses105′ and spacing between the radial supports208′. The structure is simpler and more ingenious, the processing is easy, and the battery post104″ does not need to be additionally provided with any air-guide duct. Therefore, a region on the battery post104″ for assembling the conductive member201is not affected. In addition, a size of the conductive member201may be maximized, to increase a size of the notch and ensure sensitivity in pulling apart the notch. In this embodiment, there are three radial bosses105′ disposed at equal intervals, to ensure both connection stability and air permeability. In another embodiment, there may be another quantity of radial bosses, for example, four or more radial bosses.

Outer end surfaces of the ceramic rings207and207′ are each formed in a stepped structure having an inner ring and an outer ring. The battery posts104,104′, and104″ are in embedded connection with the inner rings. A difference lies in that in an embodiment of a one-piece radial boss105, the inner ring is formed in an integral annular radial support, while in an embodiment of a separable radial boss105′, the inner ring is formed as the foregoing multiple disposed at intervals radial supports208′, thereby making the overall structure more compact and the connection more stable.

In the foregoing embodiment, to establish a current flowing path to the outside, preferably, the outer end surfaces of the ceramic rings207and207′ are tightly connected to the conductive ring216, and are specifically connected to the outer ring. The outer periphery of the flipping member202is fixedly connected to the conductive ring216. That is, the flipping member202is connected to the ceramic rings207and207′ by using the conductive ring. The conductive ring may establish a current loop between the flipping member and the outside. To prevent the conductive ring from being still electrically connected to the battery post after the notch is pulled apart, and invalidating the function of the current interrupt, preferably, the conductive ring216is tightly connected to the outer ring of the ceramic ring to be insulated from the battery post. In other words, the battery posts104,104′, and104″ are insulated from the conductive ring216by using the ceramic ring. Moreover, the conductive ring216is tightly connected to the ceramic ring so that the outer periphery of the flipping member can be sealed, and the air pressure inside the case can act on the flipping member without leakage.

To implement stable connection between the conductive ring and the flipping member, an outer end surface of the conductive ring216includes an L-shaped rabbet, and an inner end surface of the conductive ring216is used for connecting to the outer ring of the ceramic ring. The outer periphery of the flipping member202is embedded in and supports the L-shaped rabbet. In addition, the outer periphery is tightly connected to the L-shaped rabbet by using a covering cap210covering the flipping member202. Therefore, the current interruption device200can be protected while stable sealing and assembling of the flipping member202are implemented. Moreover, the conductive ring216may establish a current loop to the outside world by connecting to the covering cap or by using electrode guide pieces directly connected to each other. For example, adjacent single-cell batteries100or adjacent battery modules may be connected to each other by using electrode guide pieces.

In order that the ceramic rings207and207′ are easily and tightly connected to the cover plate102, preferably, inner end surfaces of the ceramic rings207and207′ are tightly connected to the transition ring209. The transition ring209may be connected to the ceramic rings207and207′ with ceramic brazing. In addition, the transition ring209is tightly connected to the cover plate102. The transition ring209may further be used so that the ceramic rings207and207′ and the cover plate102are disposed at intervals. Because the ceramic rings207and207′ are not directly assembled with the cover plate102, the cover plate102can be protected from high temperature caused during brazing of the ceramic ring. Moreover, areas of the ceramic rings207and207′ are not limited by a need of being directly assembled with the cover plate102. In addition, no specific design is required for the ceramic rings207and207′, so that manufacturing and assembling are convenient.

As shown inFIG. 3,FIG. 8, andFIG. 10, preferably, the transition ring209has an inner ring and an outer ring that form a Z-shaped structure. The cover plate102includes a through hole through which the battery posts104,104′, and104″ pass. An end surface of the through hole is in a staircase structure. The inner ring of the transition ring is embedded in and supports the staircase structure. That is, inFIG. 3,FIG. 8andFIG. 10, the inner ring is located at the bottom and is in embedded into the through hole, thereby increasing a contact area of the two and ensuring connection stability.

Therefore, in the foregoing embodiment, to implement the current interruption device200, the outer periphery of the flipping member202needs to be sealed. Specifically, the ceramic rings207and207′ are tightly connected between the outer periphery of the flipping member and the cover plate, thereby implementing stable and reliable operation of the current interruption device by using a ceramic sealing structure. In such a ceramic sealing structure, tight connections between the cover plate and the transition ring, between the transition ring and the ceramic ring, between the ceramic ring and the conductive ring, and between the conductive ring and the flipping member enable the air pressure inside the case to effectively act on the current interruption device, so that the operation of the current interruption device is reliable. During assembling, to ensure leak tightness of the current interruption device, the ceramic rings207and207′ are separately and tightly connected to the conductive ring216, the battery posts104,104′, and104″, and the transition ring209with ceramic brazing. That is, the conductive ring216, the battery posts104,104′, and104″, and the transition ring209first form an independent assembly, and then the transition ring209is assembled to the cover plate102with laser welding. The assembling manner is convenient and the ceramic ring does not need to be welded to the cover plate with brazing. Moreover, the conductive member201may be connected to the battery posts104,104′, and104″ with laser welding. The flipping member and the conductive member may be connected to each other with laser penetration welding or by using the foregoing boss welded structure, or in another manner. The covering cap210and the conductive ring may be connected to each other with laser welding. In addition, the battery posts104,104′, and104″ and a guide piece of the battery cell may be welded together with laser welding, to complete the overall assembly of the current interruption device.

The structure of the current interruption device200is mainly described above. The following describes a disposition manner of the current interruption device200.

To ensure normal and timely operation of the foregoing air pressure-driven current interruption device200, a size of the current interruption device200may be designed relatively large. In this way, if air pressure cannot be changed, pulling strength can be increased by increasing a force receiving area. For example, an area of the flipping member is designed relatively large to increased pulling strength of the flipping member. In the embodiment shown inFIG. 1, the current interruption device200is designed to extend out of the cover plate102along the radial direction, to increase the size. In this case, in the battery module, there are multiple single-cell batteries100. To prevent the current interruption device200extending outwards from affecting an electrode terminal in adjacent single-cell batteries100, preferably, between the adjacent single-cell batteries100, the current interruption device200and an adjacent electrode terminal are staggered in a direction of extension of the cover plate. This can fully use a region, in which no electrode terminal101is disposed, on the cover plate102, so that the protruding current interruption device does not affect a structure in the cover plate, and occupancy of space inside the battery pack can be fully reduce, thereby increasing energy density in the inclusion body. It should be noted that, herein and in the following description of the present disclosure, a meaning of “between the adjacent single-cell batteries”, “between the current interruption device and the adjacent electrode terminal”, or “between adjacent electrode terminals” refers to connection of adjacent features between different single-cell batteries, instead of connection of adjacent features in a same single-cell battery.

In this embodiment, the current interruption device200and the adjacent electrode terminal101are staggered in the direction of extension of the cover plate. In another embodiment, the current interruption device200and the adjacent electrode terminal101may alternatively be staggered in a height direction.

In an embodiment, as shown inFIG. 1, between the adjacent single-cell batteries100, the current interruption device200is connected to the adjacent electrode terminal by using an L-shaped connecting member214. The L-shaped connecting member214has a cover portion211and a guide portion212. The cover portion211covers and is connected to the current interruption device200. The guide portion212extends to the adjacent electrode terminal, to be adjacent to the electrode terminal. The L-shaped connecting member shown inFIG. 1is first aligned with the electrode terminal in the direction of extension of the cover plate, and then extends to the electrode terminal. In another embodiment, alternatively, the L-shaped connecting member may first extend to an adjacent cover plate, and then extends to the electrode terminal, to implement electrical connection between the two.

In another embodiment, as shown inFIG. 2, between the adjacent single-cell batteries100, the current interruption device200includes a covering cap210covering the flipping member202. The covering cap210extends along the cover plate102, to be aligned with the adjacent electrode terminal, that is, has the cover portion211and the introduction portion212that are disposed linearly, and is connected to the adjacent electrode terminal by using a linear I-type connecting member215. The I-type connecting member215may be further configured to connect other electrode terminals101between the single-cell batteries100and in which the current interruption device200is not disposed. In this way, with the covering cap210in such shape, the entire battery module basically may need only this type of connecting member.

Different from the embodiment shown inFIG. 2, as shown inFIG. 12, alternatively, the single-cell battery100may be enlarged to adapt to a relatively large current interruption device. Specifically, between the single-cell batteries100, a width of a single-cell battery100provided with the current interruption device200is greater than a width of the single-cell battery not provided with the current interruption device200. In addition, the current interruption device200extends close to an edge of the width of the cover plate102, so that the current interruption device200can also be adapted to.

Moreover, because the corresponding single-cell battery is wide, the current interruption device can be caused not protrude the cover plate, so that the adjacent electrode terminals can be aligned with each other. This can also avoid impact of the current interruption device200extending out of the cover plate102on a welding structure or another structure of the adjacent cover plate102. In addition, preferably, the current interruption device and the adjacent electrode terminal can be caused to be connected to each other by using the linear I-type connecting member215.

Moreover, during use, although the width of the single-cell battery100is increased, a capacity of the battery cell is not increased. That is, a battery cell capacity of the single-cell battery100provided with the current interruption device200is the same as a battery cell capacity of the single-cell battery100not provided with the current interruption device. Therefore, existence of single-cell batteries with different capacities in a same module is avoided, thereby avoiding impact on a BMS. Because of the same battery cell capacity, residual space inside the case may be filled up by using a partition plate. That is, the battery cell is surrounded by the partition plate, so that an assembling structure of the battery cell is stable. Comprehensively considers the size of the battery module and the size of the single-cell battery, a ratio of the size of the battery cell to the size of the partition plate may be 1:1 to 2:1. The partition plate may be made of an electrolyte resistance material.

Moreover, considering a current interrupt effect, costs, and assembling, in the multiple single-cell batteries100in the same module, the number of single-cell batteries provided with the current interruption device200needs to be not greater than three. Preferably, the number of single-cell batteries provided with the current interruption device200is three. Preferably, the single-cell batteries provided with the current interruption device200is single-cell batteries located on an end portion and in the central part of the battery module. If the battery module includes n sequentially arranged single-cell batteries, the single-cell batteries on the end portion of the battery module are a first single-cell battery of the battery module and an nthsingle-cell battery of the battery module. When n is an odd number, the single-cell battery in the central part of the battery module is the ((n+1)/2)thsingle-cell battery of the battery module. When n is an even number, the single-cell battery in the central part of the battery module is the (n/2)thsingle-cell battery or the ((n+2)/2)thsingle-cell battery of the battery module, where n>3.

The current interruption device, the single-cell battery, and the battery module provided in the embodiments according toFIG. 1toFIG. 12, features such as a boss welded structure, an elliptical notch, and a ceramic ring according to the embodiments ofFIG. 1toFIG. 12without departing from the idea of the present disclosure all can be applied to the following other embodiments. The following describes a single-cell battery according to another embodiment of the present disclosure with reference toFIG. 13toFIG. 17.

As shown inFIG. 13toFIG. 15, an embodiment provides a single-cell battery1100. The single-cell battery1100includes a case, a battery cell accommodated in the case, an electrode terminal1101electrically connected to the battery cell, and a cover plate1102for sealing the case. The electrode terminal1101is disposed on the cover plate1102, to input and output currents. The single-cell battery1100further includes a current interruption device1200in communication with gas inside the case. Different from the manner of being mounted on the electrode terminal in the embodiment according toFIG. 1toFIG. 12, the current interruption device1200is disposed on the cover plate and is in communication with the gas inside the case. The current interruption device1200has a conductive member1201and a flipping member1202electrically connected to the conductive member1201. The flipping member1202and the conductive member1201can be electrically disconnected from each other under action of air pressure. That is, the operating principle of the current interruption device1200is basically the same as that of the current interruption device in the embodiments according toFIG. 1toFIG. 12. In both operating principles, a circuit is disconnected due to flipping of the flipping member implemented by sensing the air pressure inside the single-cell battery.

As shown inFIG. 17, because the current interruption device1200is not disposed on the electrode terminal, the conductive member1201has a body portion1299connected to the flipping member1202and a connecting portion1298extending from the body portion1299to the electrode terminal1101and connected to the electrode terminal1101. Therefore, in this embodiment, the current interruption device1200is disposed on the cover plate. This can avoid an increase in the height of the electrode terminal1101, thereby increasing battery capacity density by using a length space of the cover plate.

As shown inFIG. 15toFIG. 17, in this embodiment, the body portion1299of the conductive member1201is in communication with gas inside the case and includes a notch1205. The notch1205is disposed around a connection point for connecting to the flipping member1202. In this way, the notch can be pulled apart under internal air pressure, thereby disconnecting the electrical connection between the flipping member and the conductive member. Further, the notch1205includes an air vent1206. In this way, the air vent1206may be used to enable the air pressure to be applied to the flipping member1202, and the flipping member is used to apply tensile force to the notch. In addition, the notch1205can be easily pulled apart at a location of the air vent1206, thereby improving sensitivity of the flipping member1202. In this case, the notch may be alternatively disposed in the flipping member. There may be multiple air vents1206disposed at intervals along the notch1205. Moreover, for features of the notch, the air vent, and the like, all features in the embodiments according toFIG. 1toFIG. 12can be applied to this embodiment. In another embodiment, the body portion of the conductive member and the flipping member may be separately provided with notches. In this way, when the air pressure inside the case increases continuously, in addition to pulling apart the notch in the conductive member, the notch in the flipping member may further be pulled apart. In this case, the gas inside the battery can be discharged from the flipping member to the outside, thereby avoiding a further increase in the air pressure inside the case of the single-cell battery. Moreover, a gas sensor inside an inclusion body of the battery may be alternatively caused to sense an alarm or disconnect a circuit. This part is to be described in detail below.

Specifically, the notch1205in the body portion can be pulled apart under action of first air pressure inside the case, the notch in the flipping member can be pulled apart under action of second air pressure inside the case, and the second air pressure is greater than the first air pressure. That is, strength of the notch in the body portion of the conductive member is less than strength of the notch in the flipping member, so that the notch in the body portion of the conductive member can be pulled apart by the smaller first air pressure. The notch in the flipping member is not further pulled apart for pressure relief unless the air pressure continues to increase.

In this embodiment, to ensure that the flipping member1202can be under action of the air pressure inside the case, the outer periphery of the flipping member1202is tightly connected to the conductive member1201, to prevent gas from leaking from the outer periphery of the flipping member and prevent pressure relief. Specifically, the cover plate1102includes an air vent in communication with gas inside the case, and the cover plate is tightly connected to a first ceramic ring1207surrounding the air vent. The body portion1299is tightly connected to the first ceramic ring1207, so that internal air pressure can be applied to the body portion1299instead of leaking to the outside. Moreover, to stably assemble the flipping member1202, the outer periphery of the flipping member1202is tightly connected to a second ceramic ring1296, and the second ceramic ring is tightly connected to the conductive member1201. Therefore, with the insulation feature of the second ceramic ring, the outer periphery of the flipping member1202can be stably supported, and the conductive member can be insulated from the outer periphery of the flipping member1202by using the second ceramic ring1296. In this way, after the flipping member1202and the conductive member1201can maintain current disconnection after the notches1205are pulled apart, thereby interrupting the current.

Specifically, as shown inFIG. 16andFIG. 17, the body portion1299of the conductive member1201includes an annular boss1297surrounding the notch1205. In this way, with the structure of the annular boss1297, an inner side of the annular boss1297in a radial direction may be used for forming the notch1205and other features, and a rear concave portion of the annular boss1297tightly accommodates the first ceramic ring1207. Moreover, an outer side of the annular boss1297may be used to tightly support the second ceramic ring1296. In this way, in this embodiment, with the unique feature of the conductive member1201shown inFIG. 16andFIG. 17, the current interruption device1200can be more easily mounted.

Moreover, the first ceramic ring1207is tightly connected to the cover plate1102by using a transition ring1209. As shown inFIG. 17, the transition ring1209has a connecting body embedded into an inner wall of the air vent and a flange ring for connecting to the first ceramic ring1207. The flange ring protrudes from the connecting body along the radial direction and presses tightly against the cover plate. Therefore, stable mounting of the current interruption device1200is ensured, and the first ceramic ring1207does not need to be directly connected to the cover plate1102.

In this embodiment, for convenience of connection, preferably, as shown inFIG. 17, the electrode terminal1101includes a battery post1104passing through the cover plate1102and electrically connected to the battery cell. As shown inFIG. 14andFIG. 16, a connecting portion1298of the conductive member1201includes a slot1295. The battery post1104penetrates the slot1295, and the battery post1104is welded to the slot1295, so that the battery post1104is stably connected to the conductive member1201. Moreover, as shown inFIG. 15, the current interruption device1200includes a connecting member1210covering the flipping member1202and electrically connected to the flipping member1202. The connecting member1210has a cover portion1294covering the flipping member1202and a guide portion1293extending from the cover portion1294. The connecting member1210may be formed in a structure the same as that of the L-shaped connecting member214in the embodiment according toFIG. 1toFIG. 12. That is, the cover portion and the guide portion form an L-shaped connecting member. In this way, a current can be easily guided from the current interruption device1200to an adjacent electrode terminal or out of a module.

In a battery module in which at least one of the single-cell batteries is the single-cell battery1100, the current interruption device extends out of the cover plate in a radial direction, thereby increasing a force receiving area and increasing pulling strength. Between adjacent single-cell batteries, the current interruption device and an adjacent electrode terminal are staggered in a direction of extension of the cover plate1102, to avoid affecting the structure of an adjacent cover plate. Moreover, the same as the embodiment according toFIG. 1toFIG. 12, there are a maximum of three single-cell batteries1100that are provided with the current interruption device1200.

The single-cell battery provided in the embodiments according toFIG. 13toFIG. 17is described above, and different feature according to the embodiments ofFIG. 1toFIG. 12are mainly described. These features of the embodiments may be replaced with each other or combined when there is no contradiction. For this, details are not described herein again in the present disclosure.

The following describes a single-cell battery2100according to an embodiment of the present disclosure with reference toFIG. 18. The single-cell battery2100includes a case, a battery cell accommodated in the case, an electrode terminal2101electrically connected to the battery cell, and a cover plate2102for sealing the case. The electrode terminal2101is disposed on the cover plate2102. The single-cell battery includes a first electrode guide member2298electrically connected to the battery cell, and a second electrode guide member2297electrically connected to the electrode terminal2101. The cover plate2102is further provided with an explosion relief valve2200in communication with gas inside the case. The explosion relief valve2200has a flipping member2202connecting the first electrode guide member2298and the second electrode guide member2297. That is, the two electrode guide members are connected to each other by using the flipping member2202.

The first electrode guide member2298and/or the second electrode guide member2297includes a first notch2205. The first notch2205can be disconnected under action of air pressure in the case, to interrupt a current on the first electrode guide member2298and/or the second electrode guide member2297. That is, the first notch is used so that the electrode guide member provided with the first notch is disconnected, thereby stopping transmission of the current. Therefore, the battery cell and the electrode terminal can be electrically disconnected from each other when at least one of the two electrode guide members includes the first notch, thereby disconnecting current transmission between the single-cell battery and the outside. Moreover, the flipping member2202is further provided with a second notch2299. The second notch2299can be disconnected under action of the air pressure in the case, so that the gas inside the case is discharged to the outside through the flipping member2202. That is, the second notch is used for gas release. After the second notch is disconnected, the internal gas can be discharged to the outside, thereby avoiding an explosion caused by a further increase in air pressure inside the battery, and achieving an explosion proof effect.

Specifically, the first notch can be pulled apart under action of first air pressure inside the case, the second notch can be pulled apart under action of second air pressure inside the case, and the second air pressure is greater than the first air pressure. That is, strength of the first notch2205is less than that of the second notch2299, so that the first notch2205can be pulled apart by the smaller first air pressure. The second notch2299is not further pulled apart for pressure relief unless the air pressure continues to increase.

As shown inFIG. 18, in this embodiment, the two electrode guide members may be in an elongated sheet structure, so that the current can be interrupted. The first notch2205extends from an edge on one side to an edge on the other side along a width direction of the elongated sheet structure. In this way, the elongated sheet structure can be broken in a timely manner along the first notch. The flipping member2202may be provided with an annular outer wall. The two electrode guide members may be fixedly connected to the annular outer wall, to implement current transmission. Specifically, in the present disclosure, the annular outer wall of the flipping member may be formed by using, for example, a boss in a boss welded structure. In addition, the flipping member is further formed in a conical ring structure. The conical ring obliquely extends outwards from the boss to an outer periphery of the flipping member, to form the flipping member in a bowl shape. Moreover, the second notch may be formed in an annular shape around the periphery of the flipping member, so that the second notch can be completely disconnected under action of the air pressure, thereby improving gas pressure relief efficiency. Specifically, the second notch may be formed in the conical ring structure. To enable the flipping member to be effectively under action of the air pressure to pull apart the first notch and the second notch, the outer periphery of the flipping member2202is tightly connected to and insulated from the cover plate in a relatively fixed manner. Therefore, on the one hand, gas can be prevented from being discharged to the outside when the first notch and the second notch are not pulled apart and the two notches are not effectively used. On the other hand, the cover plate can be prevented from being electrified with insulated connection.

In this embodiment, the electrode terminal2101includes a battery post passing through the cover plate. The battery post is insulated from and connected to an outer side of the cover plate by using the second ceramic ring, to facilitate establishment of a current loop with the outside. That is, current transmission between adjacent single-cell batteries is implemented with interconnection between electrode terminals. Use of the ceramic ring can prevent the cover plate from being electrified. Moreover, a first ceramic ring2207is tightly connected between the outer periphery of the flipping member2202and the cover plate, and is similarly used for sealing and insulation.

Moreover, to facilitate connection to the flipping member2202, a first transition piece2295is fixedly connected to the cover plate2102, and a second transition piece2296is fixedly connected to a periphery of the flipping member2202. The first transition piece and the second transition piece may be aluminum sheets. The first transition piece2295and the second transition piece2296are coaxially in brazing connection with the first ceramic ring2207. In this way, during assembling, the two transition pieces are first welded to the first ceramic ring with brazing, and then two fixing pieces are welded to another structure. This can avoid high temperature generated by brazing of the first ceramic ring and the structure such as the cover plate. Therefore, assembling is easily performed, the first ceramic ring2207is used to implemented tight, stable, and insulated connection, and the cover plate2102can be prevented from being electrified.

Specifically, the first transition piece2295and the second transition piece2296may be annular structures to fit two annular end surfaces of the first ceramic ring. Moreover, preferably, the cover plate2102includes an annular boss. The first transition piece2295is supported in the annular boss. The first ceramic ring presses tightly against an inner wall of the annular boss and extends towards the second transition piece2296, so that the first ceramic ring is stably connected inside the cover plate2102.

Moreover, the explosion relief valve further includes a protective film2099that can be torn by punching by the air pressure. The protective film tightly covers the flipping member2202, and specifically, is connected to the first transition piece2295away from the flipping member. In this way, normally, the protective film2099can protect the inner part of the explosion relief valve2200, and can be torn by punching by certain air pressure, for example, second air pressure, when explosion proof is required, thereby avoiding impact on an explosion proof effect of the explosion relief valve.

Moreover, in the present disclosure, in order that the two notches are sequentially pulled apart, a ratio of a residual thickness of the first notch to a residual thickness of the second notch is 1:3 to 1:1.2, and further, is 1:2 to 1:1.3.

The single-cell battery provided in the embodiment according toFIG. 18of the present disclosure is described above. The following describes an embodiment according to the present disclosure with reference toFIG. 22andFIG. 23.

This embodiment provides a single-cell battery3100and a battery module using the single-cell battery. The single-cell battery3100includes a case, a battery cell accommodated in the case, a cover plate3102for sealing the case, and an electrode terminal3101disposed on the cover plate3102. The single-cell battery3100further includes an internal guide member3299electrically connected to the battery cell and a current interruption device3200connected between the internal guide member3299and the electrode terminal3101. Different from the manner of being mounted on the outer end of the battery post in the embodiments according toFIG. 1toFIG. 12, the current interruption device3200in this embodiment is located at the inner side of the cover plate3102and is in communication with gas inside the case, to be capable of interrupting, under action of air pressure, a current flowing through the current interruption device3200. An adaptor portion3298extending outwards from an outer periphery along a radial direction is connected to the electrode terminal3101, so that the electrode terminal3101is connected to the outer periphery of the current interruption device by using the adaptor portion3298.

In this way, the adaptor portion3298extending outwards from the outer periphery of the electrode terminal in the radial direction is used, so that compared with a manner of being directly connected to the electrode terminal, an area of the current interruption device whose outer side is connected to the adaptor portion3298in the radial direction can be designed larger, thereby increasing an area in which the internal air pressure applies force to the current interruption device. In this way, force received by the current interruption device can be increased while the air pressure remains unchanged, thereby improving sensitivity of the current interruption device3200, and implementing a current interrupt in timely manner. Particularly, when the battery of the present disclosure is applied in the field of large batteries such as power batteries, a high current usually needs to be transmitted. Therefore, addition of the adaptor portion and enlarging the size of the current interruption device can both facilitate transmission of the high current.

In this embodiment, the adaptor portion3298is formed in an annular structure. An inner periphery of the annular structure is connected to the outer periphery of the electrode terminal, and the outer periphery is connected to the outer periphery of the current interruption device, so that the area of the current interruption device is increased. In another embodiment, the adaptor portion3298may alternatively be a structure of multiple connection posts extending along the radial direction and disposed at intervals along a circumferential direction. This can also increase the area of the current interruption device.

In this embodiment, to increase tightness of the adaptor portion with the electrode terminal and the current interruption device, and ensure stable current transmission, preferably, the inner periphery of the annular structure fits a rabbet in an outer periphery of an inner end of the electrode terminal. Specifically, the outer periphery of the inner end of the electrode terminal includes a rabbet, and the inner periphery of the adaptor portion is embedded into and connected to the rabbet. In this way, a connection area is increased, so that current transmission efficiency is improved while stability of the connection is ensured. Inner and outer ends of the electrode terminal are defined relative to the case along an axial direction of the electrode terminal. That is, an end close to the inner part of the case is the inner end.

Moreover, in this embodiment, the outer periphery of the annular structure protrudes inwards the case. That is, the annular structure is formed in an annular cap structure, and the current interruption device fits the rabbet at the inner side of the outer periphery. This not only ensures stability of the connection and improves the current transmission efficiency, but also can space the current interruption device and the electrode terminal, thereby providing space for disconnecting the current interruption device under action of the air pressure.

In this embodiment, the internal guide member3299includes a connecting piece (not shown) connected to the battery cell. The connecting piece extends towards the cover plate from the battery cell. Moreover, the internal guide member further includes a support groove for accommodating and mounting the current interruption device, and connecting plates extending towards opposite directions from the support groove. The connecting plates are separately in insulated connection with the cover plate, thereby preventing the cover plate from being electrified. Specifically, the connecting plates and a connecting groove may form an integral sheet-like structure. That is, the connecting groove includes two side walls and one bottom wall. The two side walls are respectively connected to the connecting plates at two sides. Moreover, to cause the current interruption device to be in communication with the gas inside the case, the bottom wall of the support groove may be designed to be provided with an air passing hole in communication with the gas inside the case.

In this embodiment, to prevent the cover plate from being electrified, the internal guide member3299is in insulated connection with the inner side of the cover plate3102by using a ceramic member3296. Specifically, the ceramic member3296may be formed as a ceramic sheet, and is in welded connection with the internal guide member3299and the cover plate by using transition pieces3294. That is, there are two transition pieces3294. The transition pieces may be aluminum sheets, located separately on upper and lower surfaces of the ceramic member3296. The ceramic member3296is in welded connection with the cover plate3102by using the transition piece3294located on the upper surface of the ceramic member3296. In addition, the ceramic member3296is further in welded connection with the internal guide member3299by using the transition piece3294located on the lower surface of the ceramic member3296. In this way, welded connection between the ceramic member3296and the cover plate3102and between the ceramic member3296and the internal guide member3299are more easily implemented, and the welded structure is stable. The ceramic member3296may be connected to the transition pieces3294located on the upper and lower surfaces of the ceramic member3296with ceramic brazing. The transition piece3294located on the upper surface of the ceramic member3296may be connected to the cover plate3102with laser welding. The transition piece3294located on the lower surface of the ceramic member3296may be connected to the internal guide member3299with laser welding.

In this embodiment, the current interruption device3200has a conductive member3201and a flipping member3202connected to the conductive member3201for mutual electrical connection. In addition, the flipping member3202and the conductive member3201can be electrically disconnected from each other under action or air pressure. The conductive member3201is connected to the internal guide member3299and includes an air-guide hole3213in communication with gas inside the case. Specifically, the conductive member3201is embedded in and connected to a support groove of the internal guide member. In this way, an air passing hole formed in the support groove may be in gas communication with the air-guide hole3213, so that the flipping member3202can feel pressure applied by the gas inside the case, thereby disconnecting the electrical connection between the flipping member3202and the conductive member3201under action of internal air pressure. An outer periphery of the flipping member3202and an outer periphery of the adaptor portion3298are connected to each other to establish a current connection path.

In this embodiment, in a manner of disconnecting the electrical connection, the conductive member3201includes a notch, and the notch is disposed surrounding a connection point for connecting to the flipping member3202. In this way, under action of the internal air pressure, the notch is pulled apart, thereby disconnecting the electrical connection between the conductive member and the flipping member. In another embodiment, the notch may alternatively be formed in the flipping member or a manner of pulling apart a connection point between the two may be used. To apply the air pressure to the flipping member3202, the outer periphery of the flipping member3202is in supporting connection with the conductive member3201and/or the internal guide member3299by using an insulation member3295, thereby implementing assembling of the flipping member3202by using the insulation member3295. This can ensure that the outer periphery of the flipping member is insulated from the internal guide member3299and the conductive member, thereby preventing the flipping member from still being electrically connected to the conductive member or the internal guide member at the outer periphery after the flipping member is electrically disconnected from the conductive member under action of the air pressure.

Specifically, the insulation member may be an annular insulation member such as a ceramic ring or a sealing ring. There are three connection manners for the insulation member. In a first manner, the insulation member tightly supports the conductive member3201, and specifically, supports a region in the conductive member3201that surrounds a region that is pulled apart. In a second manner, the insulation member supports the internal guide member3299, and specifically, supports a region of the internal guide member3299that surrounds the conductive member3201. In a third manner, the insulation member supports both the internal guide member3299and the conductive member3201. That is, as shown inFIG. 23, the insulation member supports a region connecting the internal guide member3299and the conductive member3201.

To ensure stable current transmission between the conductive member and the flipping member, especially, to be applicable to a high-current power battery, similar to the embodiments according toFIG. 1toFIG. 12, if the conductive member includes a notch3205, as shown inFIG. 23, the flipping member3202and the conductive member3201are connected to each other by using a boss welded structure surrounded by the notch3205. The boss welded structure includes a boss3203, a connection hole3204accommodating the boss3203, and an annular welding spot3217located between the boss3203and the connection hole3204, thereby ensuring effective passing of a high current. Specifically, as shown inFIG. 23, different from what is shown inFIG. 6, the boss3203is formed in the flipping member3202while the connection hole3204is formed in the conductive member3201. In addition, alternatively, a case that is the same asFIG. 6may be used, that is, the boss is formed in the conductive member3201, and the connection hole3204is formed in the flipping member.

Moreover, as shown inFIG. 22, the conductive member3201may be formed in a cap-shaped structure. The cap-shaped structure includes a cap body connected to the flipping member and a cap brim surrounding the cap body. The cap brim includes the air-guide hole and is connected to the internal guide member. The cap body protrudes towards the flipping member. The flipping member is formed with a sheet-like structure, and the insulation member3295is connected between an outer periphery of the sheet-like structure and the cap brim. Therefore, the structure of the current interruption device provided in the present disclosure is compact, and assembling is stable.

In this embodiment, to establish a current loop to the outside, preferably, the electrode terminal3101includes a battery post3104passing through the cover plate. The battery post is in insulated connection with the cover plate by using the ceramic ring3293, thereby preventing the cover plate from being electrified. Moreover, the adaptor portion3298is connected to an inner end of the battery post to establish a current loop to the outside by using a part protruding out of the cover plate. Specifically, the ceramic ring3293is tightly connected to an outer surface of the cover plate and is tightly connected to the battery post3104, to ensure a sealing effect inside the cover plate. An air hole3292is formed through the battery post along an axial direction. In this way, in a process of disconnection under pressure, the current interruption device3200is not affected by air pressure of a closed cavity in the cover plate but can have a pressure difference with the outside atmospheric air, so that the flipping member3202can make a movement under action of the pressure difference between the internal pressure and the external pressure to pull the notch3205apart.

The single-cell battery provided in the embodiments according toFIG. 22andFIG. 23is described above. The following describes an embodiment of the present disclosure with reference toFIG. 24.

This embodiment provides a single-cell battery4100and a battery module using the single-cell battery. The single-cell battery4100includes a case, a battery cell accommodated in the case, an electrode terminal4101electrically connected to the battery cell, and a cover plate4102for sealing the case. The electrode terminal4101is disposed on the cover plate4102. The electrode terminal includes a battery post4104passing through the cover plate4102and electrically connected to the battery cell by using an internal guide member4196. The single-cell battery further includes a current interruption device4200mounted on the battery post4104. The current interruption device4200has a flipping member4202that is fixed relative to the cover plate4102and that is in communication with gas inside the case. In addition, the flipping member4202is connected to an outer end surface of the battery post4104by using a connection point. The connection point can be disconnected under action of air pressure. In this way, the operating principle of the current interruption device in this implementation is to directly separate the flipping member4202from the battery post4104at the connection point with the air pressure, thereby disconnecting the electrical connection between the flipping member4202and the battery post4104.

To improve sensitivity, preferably, the flipping member4202is connected to the battery post by using a single welding spot4199. For example, the welding spot4199created with spot welding is used. In addition, another welding means such as laser welding may be used for implementation. Therefore, in this implementation, weld penetration and weld width of the welding spot are properly set, to control tensile pressure.

In this implementation, similar to the embodiments according toFIG. 1toFIG. 12, the battery post4104includes an air-guide hole4103in communication with the inner part of the case, so that the internal air pressure can be easily guided to the current interruption device. Moreover, to further improve reliability of the current interruption device, preferably, the flipping member4202includes a notch4205. The notch4205is disposed surrounding a connection point. In this way, in addition to pulling apart the connection point, pulling the notch4205apart may also be used to interrupt a current. In this implementation, the air pressure for pulling apart the connection point is different from air pressure for pulling apart the notch. Specifically, the connection point can be pulled apart under action of first air pressure inside the case, and the notch4205can be pulled apart under action of second air pressure. The second air pressure is greater than the first air pressure. In this way, the notch4205can be used as a backup measure of the connection point, to ensure battery safety. More preferably, the flipping member4202is covered by a covering cap4210. The covering cap4210includes an air hole4197. In this way, after the notch4205is pulled apart, the gas inside the case passes through the flipping member and is then discharged from the air hole4197, thereby implementing pressure relief inside the battery, and preventing explosions inside the battery. This principle is similar to that of the explosion relief valve in the embodiment according toFIG. 18.

In this implementation, a first ceramic ring4207is connected between the battery post4104and the cover plate4102, so that the battery post is stably mounted by using the ceramic structure and the cover plate4102is prevented from being electrified. Moreover, a second ceramic ring4198is tightly connected between the battery post4104and an outer periphery of the flipping member, so that the outer periphery of the flipping member can be sealed by using the ceramic structure, thereby ensuring that the internal gas can effectively apply pressure to the flipping member and that the battery post is insulated from the outer periphery of the flipping member, and preventing the flipping member from being still conductive after the connection point or the notch is pulled apart.

Specifically, in an embodiment, the battery post4104has an annular boss4297surrounding the connection point. The first ceramic ring4207is tightly accommodated in a rear concave portion of the annular boss4297. The first ceramic ring4207is tightly connected to the cover plate4102. A radial outer side of the annular boss4297tightly supports the second ceramic ring4198. The second ceramic ring4198tightly supports the outer periphery of the flipping member4202. In this way, the overall structure of the current interruption device is more compact, and the assembling is stable. For ease of assembly, the first ceramic ring4207is tightly connected to the cover plate4102by using a transition ring4209. Specifically, ceramic brazing may be performed on the transition ring and the first ceramic ring4207for the tight connection.

Some embodiments of the present disclosure are described above. The following describes an embodiment of the present disclosure with reference toFIG. 5toFIG. 7,FIG. 20, andFIG. 21. This embodiment provides a single-cell battery and a battery module. Effects of features that are the same as those in the foregoing embodiments are not described in detail herein again.

This embodiment provides a single-cell battery. The single-cell battery100includes a case109, a battery cell108accommodated in the case109, an electrode terminal101electrically connected to the battery cell108, and a cover plate102for sealing the case. The electrode terminal101is disposed on the cover plate102. The electrode terminal includes a battery post104″′ passing through the cover plate102and electrically connected to the battery cell. The single-cell battery further includes a current interruption device200mounted on the battery post104″′. The current interruption device200is in communication with gas inside the case. The current interruption device200has a conductive member201and a flipping member202connected to the conductive member201for mutual electrical connection. In addition, the flipping member202and the conductive member201can be electrically disconnected from each other under action of air pressure. The conductive member201is connected to the battery post104″′ for mutual electrical connection. The flipping member202and the conductive member201are connected to each other by using a boss welded structure. The boss welded structure includes a boss203, a connection hole204accommodating the boss203, and an annular welding spot217located between the boss203and the connection hole204. The flipping member202is formed with a first sheet-like structure. The first sheet-like structure includes the connection hole204. The conductive member201is formed with a second sheet-like structure. The second sheet-like structure includes the boss203. The conductive member201includes a notch205. The notch205is disposed surrounding the boss203. The conductive member201is connected to an outer end surface of the battery post104″′. An outer periphery of the flipping member202is fixed relative to the cover plate102. The battery post104″′ is fixedly connected to the cover plate102, and the battery post104″′ includes an air-guide duct communicating an inner part of the case and the current interruption device200. The battery post104″′ is mounted in a ceramic ring207″ tightly connected to the cover plate102. An outer end surface of the ceramic ring207″ is tightly connected to a conductive ring216′. The outer periphery of the flipping member202is tightly connected to the conductive ring216′. The battery post104″′ and the conductive ring216′ are insulted by using the ceramic ring207″. In this way, a current is stably transmitted or interrupted.

In this embodiment, the outer end surface of the battery post104″′ includes an accommodation hole218′, and an outer periphery of the conductive member201is fixed to an inner wall of the accommodation hole.

In this embodiment, the notch205is elliptical, the boss203is circular, a center of the notch205and a center of the boss203are staggered along a direction of major axis of the ellipse, and the major axis of the ellipse and an axial line of the electrode terminal are obliquely disposed.

In this embodiment, in addition, an outer end periphery of the battery post104″′ has a radial boss105″. An inner periphery of the ceramic ring207″ has a radial support208″ supporting and connected to the radial boss105″. There are multiple radial bosses105″ disposed at intervals along a circumferential direction. There are multiple radial supports208″ disposed at intervals along the circumferential direction. The multiple radial bosses are in a one-to-one correspondence with the multiple radial supports.

In this embodiment, the outer end surface of the ceramic ring207″ is formed in a stepped structure having an inner ring and an outer ring. The battery post104″′ is in embedded connection with the inner ring. The outer ring is tightly connected to the conductive ring216′ insulated from the battery post104″′. The outer periphery of the flipping member202is fixedly connected to the conductive ring216′. An inner end surface of the ceramic ring207″ is tightly connected to a transition ring209′. The transition ring209′ is tightly connected to the cover plate102so that the ceramic ring207″ and the cover plate102are disposed at intervals.

In this embodiment, the ceramic ring207″ is tightly connected to the conductive ring216′, the battery post104″′, and the transition ring209′ with ceramic brazing.

In this embodiment, the transition ring209′ has an inner ring and an outer ring that form a Z-shaped structure. The cover plate includes a through hole through which the battery post104passes. An end surface of the through hole is in a staircase structure. The inner ring of the transition ring is embedded in and supports the staircase structure.

In this embodiment, the outer end surface of the conductive ring216′ includes an L-shaped rabbet. The outer periphery of the flipping member202is embedded in and supports the L-shaped rabbet. The outer periphery is tightly connected to the L-shaped rabbet by using a covering cap210covering the flipping member202.

To implement assembling of the single-cell battery, as shown inFIG. 20andFIG. 21, a lower spacer ring107is connected to the battery cell108, and an upper spacer ring106is connected below the cover plate102. The upper and lower spacer rings may be made of an insulating material. The single-cell battery100further includes an internal connecting sheet110connected to the battery cell. The internal connecting sheet110extends to between the upper spacer ring107and the lower spacer ring106. A lower surface of the battery post104″′ includes a staircase portion. The staircase portion passes through the cover plate102and the upper spacer ring106and is clipped to an end portion of the internal connecting sheet110. In this way, the current is transmitted from the battery cell108to the battery post104″′, and the cover plate102is insulated from the case109and prevented from being electrified.

According to a battery module provided in this embodiment, the battery module includes multiple single-cell batteries. At least one of the single-cell batteries is the single-cell battery described above. The current interruption device200extends out of the cover plate102along a radial direction. Between adjacent single-cell batteries100, the current interruption device200and an adjacent electrode terminal are staggered in a direction of extension of the cover plate. Moreover, as shown inFIG. 1, between the adjacent single-cell batteries100, the current interruption device200is connected to the adjacent electrode terminal by using an L-shaped connecting member214. The L-shaped connecting member214has a cover portion211and a guide portion212. The cover portion211covers and is connected to the current interruption device200. The guide portion212extends to the adjacent electrode terminal.

In addition, this embodiment further provides a power battery. The power battery includes an inclusion body and a battery module accommodated in the inclusion body. The battery module is the battery module described above. A gas detection device for detecting flammable gas is disposed inside the inclusion body. The gas detection device is disposed close to the current interruption device, to provide a flammable gas signal for a charge/discharge protection system. Moreover, considering costs and the effect, the battery module needs to have only one current interruption device.

The single-cell battery having a current interruption device or an explosion relief valve is described above. The current interruption device or the explosion relief valve each implements safety measures by using a mechanical structure of the current interruption device or the explosion relief valve. The following describes in detail a power battery including a charge/discharge protection system, to improve safety with electrical control.

As shown inFIG. 19, the present disclosure provides a power battery. The power battery may be a power battery having a current interruption device or an explosion relief valve, or another type of power battery. The power battery includes an inclusion body and multiple single-cell batteries100accommodated in the inclusion body. For example, the multiple single-cell batteries100may be connected in series or in parallel to form a battery module. A gas detection device300, for example, a gas sensor, for detecting flammable gas in the power battery is disposed inside the inclusion body, to provide a signal for indicating whether to switch off a charge/discharge circuit of the power battery.

In addition to including the gas detection device300located inside the power battery, the charge/discharge protection system included in the power battery further includes a control device400and a circuit switching on/off device.

The gas detection device300feeds back a flammable gas signal to the control device400. The control device400is configured to control, according to the flammable gas signal, the circuit switching on/off device to switch off the charge/discharge circuit of the power battery control. That is, safety of the present disclosure is automatic control performed by detecting whether there is flammable gas in the inclusion body. In an emergency state such as overcharging of the battery, flammable gas is produced inside the battery. The part of gas more or less leaks to the inner part of the inclusion body in various manners. In this case, the gas detection device, for example, the gas sensor, can detect the flammable gas, and feeds back such information to the control device. The control device determines, according to whether flammable gas is detected or an amount of detected flammable gas, whether to disconnect the charge/discharge circuit of the power battery. When flammable gas is detected, or an amount of flammable gas exceeds a preset threshold, the circuit switching on/off device may be controlled to disconnect the charge/discharge circuit of the power battery, ensure safety of the power battery.

To further reduce potential risks, the power battery further includes an alarm device500controlled by the control device400. In this way, relevant personnel may be instructed, with voice, flash, or a alarm device such as a siren, to evacuate the site, thereby reducing potential risks.

As shown inFIG. 19, the control device400includes a host computer main control chip401of the power battery and a control module402in signal connection with the main control chip. The control module402is in signal connection with the circuit switching on/off device. The circuit switching on/off device may be a relay403located in the charge/discharge circuit, to be controlled by the control module402to switch off the charge/discharge circuit. Moreover, the alarm device500may be in signal connection with the host computer control chip401, to receive an alarm from an alarm instruction.

In a specific operating process, digital-to-analog conversion, sampled storage, and other processing may be performed on an acquired signal of the gas sensor. Moreover, fault detection may further be performed on the system. When no failure occurs in the system, gas concentration processing may further be performed on the acquired signal, to determine whether leakage of flammable gas occurs. When the concentration of the leakage of the flammable gas exceeds a threshold, the host computer main control chip401performs operations of interrupting the current and alarming.

In this implementation, the gas detection device is disposed outside the single-cell battery. The flammable gas may be discharged to the outside by using the current interruption device or the explosion relief valve in the foregoing implementations of the present disclosure. In addition, various known conventional explosion relief valves may be used to discharge the gas to the outside provided that the valves are capable of discharging the gas to the outside. That is, in the battery module, at least one of the single-cell batteries includes a current interruption device for disconnecting the charge/discharge circuit under action of gas pressure inside the single-cell battery, that is, the foregoing current interruption device. In addition, the current interruption device can enable gas inside a case to be discharged to the outside in a disconnected state. In this way, the gas detection device in the inclusion body can detect the flammable gas discharged to the outside. In this case, it indicates that an emergency case of overcharging of the battery occurs. In addition, to improve sensitivity of the system, preferably, the gas detection device is disposed close to the current interruption device, so that the gas detection device can detect a corresponding signal in a timely manner after the flammable gas is released, and feeds back the signal to the control device. Moreover, in addition to the current interruption device, in some implementations, at least one of the single-cell batteries includes an explosion relief valve capable of discharging gas under action of gas pressure inside the single-cell battery, for example, the explosion relief valve in the embodiment according toFIG. 18. In this case, the gas detection device may be disposed close to the explosion relief valve.

To discharge the gas to the outside, the current interruption device in each of the foregoing implementations includes a cover member. The cover member includes an air hole in communication with the outside. In this way, the gas inside the case can be discharged to the outside by using the flipping member after the flipping member and a conductive member are electrically disconnected from each other. Specifically, in this case, the flipping member may be provided with a notch that can be pulled apart by the air pressure inside the case. In the embodiments according toFIG. 13toFIG. 17, compressive strength of the notch in the flipping member may be greater than strength of the notch in the body portion of the conductive member. Alternatively, in the embodiment according toFIG. 18, compressive strength of the notch in the flipping member may be greater than strength of the notches in the two electrode guide members. In this way, a process of releasing gas after a current is interrupted is implemented. In addition, if the current interruption device in the embodiments according toFIG. 1toFIG. 12is used, the flipping member includes the foregoing notch.

Moreover, the air hole in the cover member may further enable the current interruption device to have a pressure difference with the atmospheric air, so that an action of the flipping member is implemented. The cover member herein may be the covering cap210in the embodiments according toFIG. 1toFIG. 12, or may be the connecting member1210in the embodiments according toFIG. 13toFIG. 17, or the protective film2099in the embodiment according toFIG. 18, or the like. In this way, after the corresponding notch is pulled apart, the gas can be discharged to the outside by using, for example, the air hole213in the embodiments according toFIG. 1toFIG. 12, so that the gas detection device can detect in a timely manner flammable gas that leaks to the pack.

The embodiments of the present disclosure are described in detail with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details in the foregoing embodiments. Various simple variations may be made to the technical solutions of the present disclosure within the technical idea of the present disclosure. These simple variations all fall within the protection scope of the present disclosure.

Moreover, it should be noted that, the specific technical features described in the foregoing specific embodiments may be combined in any appropriate manner when there is no contradiction. To avoid unnecessary repetitions, possible combination manners are not additionally described in the present disclosure.

In addition, the different embodiments of the present disclosure may be randomly combined, and the combinations may also be considered as content disclosed by the present disclosure provided that the combinations do not depart from the idea of the present disclosure.

Finally, the research and development background for introducing the foregoing inventive ideas of the present disclosure are described.

Environmental pollution increasingly deteriorates, development of new energy vehicles become a new national strategic plan. Currently, all-electric vehicles and plug-in hybrid vehicles of the new energy vehicles dominate the automobile market. In the field of electric vehicles, the endurance mileage is a main factor restricting the development of the electric vehicles, and the endurance mileage depends on energy density of a battery cell. Currently, there are mainly two materials: a ternary material and Lithium iron phosphate for battery cells in the market. Although with high energy density, the ternary material is poor in safety performance. Particularly, overcharging causes fires or explosions. This is a great challenge for the automotive industry having strict requirements on safety performance.

As a greater battery capacity leads to better endurance mileage, some solutions to improvement of the safety performance of the ternary material need to be used to ensure safety of the ternary. However, because it is difficult to further improve the performance of the material, a solution relating to structures needs to be considered.

As described in the related art, in the existing design of a battery pack, a BMS is mainly used to perform voltage and current temperature management and control on a battery cell in a module. However, in an actual use process, there are still incidental risks of consistency of the battery cell and reliability of management software. Specifically, referring to people's usage habits with regard to mobile devices, the people usually plug in car bodies to recharge the electric vehicles all the time. Because the BMS software is used to control the recharging, such batteries are merely recharged for a long time. However, if software detection fails or another exception occurs, a risk of overcharging of a battery cell in a loop in an inclusion body occurs. Therefore, the author of the present disclosure conceives of a design for providing mechanical protection for a battery, to prevent a battery safety risk from occurring after a software failure.

For mechanical protective measures, the author of the present disclosure creatively finds that there is a law of current interruption timing of a battery in an emergency state such as overcharging. To be specific, a current interruption device or an explosion relief valve capable of interrupting a current on an electrode terminal can be designed according to the principle that internal air pressure increases in an emergency state such as overcharging. In this way, inputting or outputting through the electrode terminal can be controlled, thereby ensuring safety.

Moreover, a capacity of a power battery used in an automobile is usually ten-odd times of that of a3C battery, and a through current the power battery is dozens or even hundreds of times of that of a minor class of battery. Therefore, the power battery further needs to withstand a very high through current. In addition, requirements on weather resistance and leak tightness of the power battery are stricter because of a usage environment. These problems are collected and then the technical solutions of the present disclosure are formed. In addition, as verified by tests, the current interruption device or the explosion relief valve in any of the implementations of the present disclosure can interrupt a current in a battery in a timely manner, thereby effectively improving safety.