CN219998308U

CN219998308U - Battery pack, vehicle, energy storage system and power supply system

Info

Publication number: CN219998308U
Application number: CN202320520354.3U
Authority: CN
Inventors: 罗英桀; 王嘉豪; 江锐; 林敏�
Original assignee: Huawei Digital Power Technologies Co Ltd
Current assignee: Huawei Digital Power Technologies Co Ltd
Priority date: 2023-03-08
Filing date: 2023-03-08
Publication date: 2023-11-10
Anticipated expiration: 2033-03-08

Abstract

The application provides a battery pack, a vehicle, an energy storage system and a power supply system. The over-temperature protection element is used for fusing when the temperature of any one of at least partial single batteries exceeds the melting point of the over-temperature protection element so as to disconnect the over-temperature detection circuit, the battery management unit is used for generating an over-temperature signal, and the battery management unit is used for controlling the battery pack to cool down according to the over-temperature signal. The battery pack provided by the application can more flexibly arrange the over-temperature protection element on the surface of the single battery, improves the sensitivity of monitoring the over-temperature of the battery pack, and does not influence the normal operation of the battery pack when the over-temperature protection element is in over-temperature fusing because the over-temperature protection element is not directly electrically connected with the single battery.

Description

Battery pack, vehicle, energy storage system and power supply system

Technical Field

The application relates to the technical field of batteries, in particular to a battery pack, a vehicle, an energy storage system and a power supply system.

Background

The battery pack is very important equipment for energy storage technology, and is widely applied to the fields of electric vehicles and photovoltaic energy storage technologies. As one of the main energy supplies in electric devices such as electric vehicles, the requirements for power density and energy density of the battery pack are increasing with the continuous development of new energy industries. High power density battery packs can generate high heat, and excessive temperature of the battery packs can cause adverse effects on the normal operation of electric equipment, and explosion can be caused when the battery packs are severe. The safety performance of the battery pack is of great interest to the industry.

In order to realize temperature monitoring of the battery pack, a thermistor with a negative temperature coefficient is generally arranged in a battery management unit at present, and the temperature of the single battery is periodically sampled and monitored. However, since the thermistor is generally hard in texture and difficult to make into a thin layer, it is disadvantageous to dispose the thermistor at a position where the gap in the battery pack is small, and the monitoring sensitivity for the over-temperature phenomenon is limited.

Disclosure of Invention

The utility model provides a battery pack, a vehicle, an energy storage system and a power supply system.

In a first aspect, the utility model provides a battery pack, the battery pack comprises a battery management unit and a plurality of single batteries, the battery management unit comprises an over-temperature detection circuit and an over-temperature protection element, the over-temperature protection element is connected in series or in parallel in the over-temperature detection circuit, the over-temperature protection element is arranged on the surface of at least part of the single batteries, the over-temperature protection element is used for fusing when the temperature of any one of the at least part of the single batteries exceeds the melting point of the over-temperature protection element so as to disconnect the over-temperature detection circuit, the battery management unit is used for generating an over-temperature signal when the over-temperature detection circuit is disconnected, and the battery management unit is used for controlling the battery pack to cool according to the over-temperature signal. The battery management unit can cool the battery pack by controlling the heat dissipation device, wherein the heat dissipation device can be located inside the battery pack or outside the battery pack.

According to the application, the over-temperature protection element is arranged on the battery pack, and the first over-temperature protection element is fused when the temperature rises to the melting point, so that the over-temperature detection circuit is disconnected, and the battery management unit is further caused to generate an over-temperature signal, so that the temperature control of the single battery can be realized, the safety performance of the battery pack is improved, and the battery pack is ensured to work in a stable state.

Secondly, compared with a thermistor, the over-temperature protection element is convenient to flexibly arrange on different surfaces or gaps of the single battery, and when the over-temperature protection element is extruded, the over-temperature protection element is not easy to damage the surface of the over-temperature protection element and the surface of the single battery where the over-temperature protection element is arranged.

Thirdly, no electric connection relation exists between the over-temperature protection element and the converging part of the single battery, even if the over-temperature protection element is fused, the electric connection between the converging part of the single battery and other devices is not disconnected, after the battery management unit takes measures to cool the single battery, the single battery can normally work, and the electric connection between the single battery and other devices is not required to be re-established, so that the operation cost can be reduced, and the stable operation of the battery pack is guaranteed.

In one implementation manner, the extending path of the over-temperature protection element is a straight line or a curve, and when the extending path of the over-temperature protection element is a curve, the extending path is used for increasing the distribution position of the over-temperature protection element on the single battery so as to improve the temperature monitoring precision of the single unit.

In one implementation manner, the over-temperature protection element is arranged as a straight line, which is beneficial to reducing operation difficulty and cost, wherein the extending direction of the straight line can be a first direction or a direction intersecting with the first direction and perpendicular to the height direction of the single battery. Illustratively, the first direction is a width direction or a length direction of the battery pack.

In one implementation, the over-temperature protection element has a melting point that is higher than the highest temperature of the cell when operating normally. In this embodiment, the temperature that satisfies the normal operation of the unit cell generally has a range, and the melting point of the over-temperature protection element is higher than the upper limit of the temperature range, so that the battery management unit only generates an over-temperature signal when the unit cell is in an over-temperature state, and further cools and dissipates heat to the battery pack.

In one implementation, the melting point of the over-temperature protection element is between the lower limit temperature and the upper limit temperature of the battery cell during normal operation, and the melting point of the over-temperature protection element is greater than the optimal operating temperature of the battery cell. The optimal operating temperature of the unit cells refers to a temperature at which the unit cells can be maintained to have high charge and discharge efficiency, and specific values can be determined according to the unit cells or the unit cell packs. In this implementation scheme, when single battery operating temperature rises to single battery's optimum operating temperature, reach the fusing point of overtemperature protection component, overtemperature protection component fuses, and overtemperature detection circuit disconnection, battery management unit send out the overtemperature signal when detecting that overtemperature detection circuit disconnection, and control cooling system cools down to the battery package to the protection battery package for the battery package can work about optimum operating temperature, makes the battery package can keep at optimum operating condition, promotes battery package work efficiency.

In one implementation, the overtemperature protection element is an alloy sheet or a metal sheet. The melting point of the alloy sheet is greater than or equal to 70 ℃ and less than or equal to 120 ℃, and the melting point of the metal sheet is greater than or equal to 70 ℃ and less than or equal to 120 ℃. In this embodiment, the alloy sheet and the metal sheet have low melting points, melt when the temperature exceeds the melting point, and both have conductivity, so that the conditions for connection to the overheat detection circuit and the battery management unit can be satisfied. Illustratively, the overtemperature protection element is a binary, ternary or quaternary eutectic alloy with a certain proportion of bismuth, cadmium, tin, lead, dysprosium, indium and other elements as main components, or the overtemperature protection element comprises any one metal of bismuth, cadmium, tin, lead, dysprosium and indium.

In one implementation manner, the over-temperature protection element comprises a plurality of over-temperature protection sub-elements which are arranged at intervals in the extending direction of the over-temperature protection element, two adjacent over-temperature protection sub-elements are electrically connected through a conductive piece, and the plurality of over-temperature protection sub-elements are arranged on the surfaces of at least part of the single batteries in the plurality of single batteries. For monitoring the temperature of the at least part of the unit cells, and can reduce costs.

In this implementation manner, the over-temperature protection subelements and the conductive members are alternately arranged in the extending direction of the over-temperature protection element, and the portion of the over-temperature protection element provided with the over-temperature protection subelements can implement over-temperature protection on the working temperature of the single battery, so that on the premise of reducing the manufacturing cost of the over-temperature protection element as much as possible, at least part of the single batteries in the plurality of single batteries can be subjected to over-temperature monitoring. The two adjacent over-temperature protection subelements are electrically connected, so that even if a plurality of over-temperature protection subelements are arranged at intervals, when any one of the over-temperature protection subelements is fused, the over-temperature detection circuit is disconnected, and the over-temperature phenomenon can not be influenced when the over-temperature protection subelements are monitored.

In one implementation, a plurality of over-temperature protection subelements are disposed on a surface of each of a plurality of cells. The scheme is favorable for further improving the temperature monitoring capability of the over-temperature protection subelement.

In one implementation, the battery management unit includes a plurality of over-temperature protection elements, the melting points of the over-temperature protection elements are different, and the over-temperature protection elements are distributed at different positions of the unit batteries. And the device is used for monitoring the working temperature of the single battery.

In this implementation manner, the plurality of over-temperature protection elements are all connected with the over-temperature detection circuit and the battery management unit, and when any one of the plurality of over-temperature protection elements is fused, the over-temperature detection circuit is disconnected, and the battery management unit generates an over-temperature signal.

In this implementation, the operating temperatures of the different locations of the battery cells are different, and when the volume of the battery cells is larger, the temperature difference between the different locations of the battery cells is larger. The over-temperature protection elements with different melting points are arranged at different positions of the single battery, and the melting points of the over-temperature protection elements correspond to the temperatures of the different positions of the single battery. By arranging the overtemperature protection element with a higher melting point at a position with a higher temperature of the single battery and arranging the overtemperature protection element with a lower melting point at a position with a lower temperature of the single battery, the two extreme cases that the overtemperature protection element is fused when the temperature is lower and the overtemperature protection element is not fused when the temperature is higher can be avoided. The over-temperature protection elements with different melting points are used in combination, so that the multi-level over-temperature monitoring function is achieved, and the accuracy and the sensitivity of the over-temperature protection elements for monitoring over-temperature phenomena are improved.

In one implementation, the over-temperature protection element is disposed at a surface of each of the plurality of unit cells. The device is used for monitoring the working temperature of each single battery and improving the detection sensitivity of the battery pack. In this implementation mode, the monitoring range of overtemperature protection element covers the surface of every battery cell in a plurality of battery cells, can realize the overtemperature detection to all battery cells in the battery package, further promotes the monitoring sensitivity of overtemperature protection element to the battery package, and overtemperature protection element is connected with overtemperature detection circuit, battery management unit electricity again for battery management unit can carry out temperature control to every battery cell in a plurality of battery cells, improves the work efficiency of battery package.

In one implementation, at least some of the plurality of unit cells are arranged adjacent to each other in sequence. The battery management unit includes a plurality of over-temperature protection elements, at least one of which is disposed between sides of two unit batteries that are adjacently disposed. So that the overheat protection element can detect the temperatures of the adjacent sides of the adjacent two unit cells.

In this embodiment, at least some of the plurality of unit cells are arranged along the first direction, so that, in order to make the battery pack more compact, the gaps between two opposite sides of the plurality of unit cells are generally smaller, and it is not suitable to provide a thermistor with a harder texture at the gaps. Because the over-temperature protection element shows fusing when the temperature rises, when the over-temperature protection element is arranged on the adjacent side surfaces of two single batteries, the surface of the single batteries cannot be extruded or even damaged, and the stability and the service life of the over-temperature protection element and the single batteries are improved.

In one implementation, each of the plurality of over-temperature protection elements is disposed between two adjacent unit cells. The scheme is favorable for improving the monitoring sensitivity of the over-temperature protection element to the side temperature of the single battery.

In one implementation, the battery pack further includes a film package including a first film and a second film stacked together, the overtemperature protection element is located between the first film and the second film, and a cavity is formed between the overtemperature protection element and at least one of the first film and the second film, and is used for accommodating a molten body melted at a fusing position in the overtemperature protection element. The fused body is separated from the part which is not fused by the over-temperature protection element, and the fusing effect is improved.

In the present embodiment, the film package serves to insulate the over-temperature protection element from the unit cell and to facilitate the installation of the over-temperature protection element. The first film, the over-temperature protection element and the second film are arranged in a laminated mode, wherein the cavity is arranged between the surface of the over-temperature protection element facing the first film and the first film, or between the surface of the over-temperature protection element facing the second film and the second film.

In one implementation, the first film and the second film are arranged along the height direction of the single battery, and the second film is provided with a cavity, so that the molten body can fall into the cavity under the action of gravity and is separated from the unmelted part of the overtemperature protection element, the breaking process of the overtemperature detection circuit is quickened, and the overtemperature detection efficiency of the battery management unit is improved. In addition, the over-temperature protection element is integrated into the film packaging piece, so that the over-temperature protection element is more convenient to replace after being melted.

In one implementation, the cavity is a groove formed in the surface of the first film or the second film facing the over-temperature protection element, and the groove is used for accommodating the molten body after the over-temperature protection element is melted.

In one implementation mode, the surface of the over-temperature protection element, which is far away from the second film, is fixed with the first film through a first adhesive layer, the surface of the over-temperature protection element, which is far away from the first film, is fixed with the second film through a second adhesive layer, through holes penetrating through two opposite surfaces of the second adhesive layer are formed in the second adhesive layer, and the through holes form the cavity. For receiving the melted over-temperature protection element portion.

In one implementation, a part of the over-temperature protection element between the first adhesive layer and the second adhesive layer is an alloy sheet, and the other part is a conductive member, wherein the part corresponding to the through hole is an alloy sheet, so that the fused melt of the alloy sheet falls into the through hole. The scheme is beneficial to reducing the manufacturing cost of the over-temperature protection element.

In one implementation, the components located between the first and second adhesive layers are all over-temperature protection elements. The scheme is favorable for improving the detection sensitivity of the over-temperature protection element.

In one implementation, the film package is sheet-like and the overtemperature protection element is "U" shaped. In the embodiment, the thin film packaging piece is arranged to be sheet-shaped, so that the over-temperature protection element and the thin film packaging piece are in integral modularization, the plurality of single batteries can be monitored simultaneously, and the assembly is convenient.

In one implementation, the sheet-like thin film package may be disposed on the side surfaces of two adjacent unit cells, and the sheet-like thin film package may not cause backlog on the side surfaces of the unit cells.

In one implementation, the film package is in the shape of a strip, and the shape of the overtemperature protection element is also in the shape of a strip matched with the film package. The thin film packaging piece in strip-shaped arrangement occupies a small area, saves cost and is flexible in arrangement mode.

In one implementation, the film package includes a cell voltage sampling circuit located between the first film and the second film and spaced apart from the over-temperature protection element.

In this implementation mode, electric core voltage sampling circuit and overtemperature protection component integrate in the film packaging piece for this film packaging piece can enough monitor the voltage in the battery cell, and can monitor the temperature of battery cell. The battery cell voltage sampling circuit is connected with the single battery and the battery management unit, and can judge whether the battery pack is overcharged or overdischarged by monitoring the voltage of the single battery, so that safety accidents are avoided. The battery cell voltage sampling circuit acquires abnormal voltage information and transmits the voltage information to the battery management unit, and the battery management unit can generate corresponding signals to solve the abnormal situation.

In the implementation mode, the battery cell voltage sampling circuit and the over-temperature detection circuit are arranged at intervals in the film packaging piece, so that the battery cell voltage sampling circuit and the over-temperature detection circuit are independent of each other and do not affect each other. The battery cell voltage sampling circuit and the over-temperature detection circuit are integrated into the film packaging piece, so that the battery cell voltage sampling circuit and the over-temperature detection circuit are more convenient to install and operate, and the integration level of the battery management unit is higher.

In one implementation, the assembly of the thin film package, the cell voltage sampling circuit, and the overtemperature protection element may also be referred to as a flexible circuit board. In order to reduce the structure, make battery package structure simpler.

In one implementation, a battery pack includes a flexible circuit board including a film package and a cell voltage sampling circuit. The over-temperature protection element is integrated in the flexible circuit board. In order to reduce the structure, make battery package structure simpler.

In one implementation, the battery pack includes a heat sink located at the bottom surface of the unit battery, and the overtemperature protection element is located between the bottom surface of the unit battery and the heat sink. For monitoring the temperature of the bottom surface of the battery pack. In this implementation mode, heat abstractor is used for being linked together with outside cooling system, when battery management unit transmits the overtemperature signal to cooling system, indicates that battery management unit monitors that the bottom surface temperature of battery cell is too high, and cooling system adjusts properties such as velocity of flow, temperature and the flow of cooling medium in the heat abstractor according to the overtemperature signal, promotes cooling medium to the radiating effect of battery cell for battery package resumes normal operating condition again, and battery management unit cooperates with heat abstractor, is favorable to in time handling the overheated problem of battery. In an embodiment, if the over-temperature protection element is replaced by a thermistor, the thermistor cannot be mounted at the gap due to the extremely small gap between the single battery and the heat dissipation device, so that temperature monitoring on the bottom surface of the single battery cannot be achieved.

In one implementation mode, a mounting hole and a containing groove are formed in one side, facing the single battery, of the heat radiating device, the mounting hole is communicated with the containing groove, and the mounting hole is located between the bottom surface of the single battery and the containing groove. The over-temperature protection element is positioned in the mounting hole, and the accommodating groove is used for accommodating the molten body after the fusing part in the over-temperature protection element is fused. The realization mode enables the fused mass to be separated from the part which is not fused and the over-temperature protection element, and improves the fusing effect.

In one implementation, the mounting hole communicates with the receiving groove in the height direction of the unit battery. The molten mass can fall into the cavity under the action of gravity and is separated from the part of the overheat protection element which is not melted, so that the breaking process of the overheat detection circuit is quickened, and the overheat detection efficiency of the battery management unit is improved.

In one implementation, the two ends of the accommodating groove along the first direction are provided with supporting parts, the two ends of the over-temperature protection element along the first direction are positioned on the supporting parts, and the supporting parts are used for preventing the over-temperature protection element from falling into the accommodating groove from the mounting hole when the over-temperature protection element is not melted.

In a second aspect, the present application provides a vehicle, which includes a vehicle body and a battery pack according to any implementation manner of the first aspect, wherein the battery pack is mounted on the vehicle body. According to the application, the over-temperature protection element is arranged in the battery pack, and the over-temperature protection element is less limited when being arranged on the surface of the single battery, so that the sensitivity of over-temperature monitoring can be effectively improved, the safety performance of the battery pack is improved, and the performance of the whole vehicle is further improved.

In a third aspect, the present application provides an energy storage system, the energy storage system including a current transformer and a battery pack according to any implementation manner of the first aspect, the current transformer including an AC/DC conversion circuit, wherein the AC/DC conversion circuit is configured to be connected to an external AC source and the battery pack, and the AC/DC conversion circuit is configured to convert AC power transmitted by the external AC source into DC power and transmit the DC power to charge the battery pack. The battery pack provided by the application is provided with the over-temperature protection element, and the over-temperature protection element is less limited when being arranged on the surface of the single battery, so that the sensitivity of over-temperature monitoring can be effectively improved, and the safety performance of the battery pack and the energy storage system is improved.

In an implementation manner, the energy storage system further comprises a photovoltaic module, the photovoltaic module is connected with the converter, the converter further comprises a DC/DC conversion circuit, and the photovoltaic module is connected with the battery pack through the DC/DC conversion circuit and is used for charging the battery pack.

In a fourth aspect, the present application provides a power supply system, where the power supply system includes a photovoltaic module and an energy storage system according to any implementation manner of the third aspect, and the converter further includes a DC/DC conversion circuit, where the photovoltaic module is connected to the DC/DC conversion circuit, and where the photovoltaic module is connected to the battery pack through the DC/DC conversion circuit and is used to charge the battery pack. According to the application, the over-temperature protection element is arranged in the battery pack, and the limitation of the over-temperature protection element when the over-temperature protection element is arranged on the surface of the single battery is small, so that the sensitivity of over-temperature monitoring can be effectively improved, and the safety performance of a power supply system is improved.

Drawings

In order to more clearly describe the technical solution in the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be described below.

FIG. 1 is a schematic view of a vehicle according to an embodiment of the present application;

fig. 2 is a schematic diagram of an application scenario of a vehicle-mounted power supply system according to an embodiment of the present application;

FIG. 3 is a schematic diagram of a power supply system according to an embodiment of the present application;

fig. 4 is a schematic structural view of a battery pack according to an embodiment of the present application;

fig. 5 is a schematic structural view of a battery pack according to an embodiment of the present application;

fig. 6 is a schematic structural view of a battery pack according to an embodiment of the present application;

fig. 7 is a schematic view of a battery pack according to an embodiment of the present application;

fig. 8 is a schematic structural view of a battery pack according to an embodiment of the present application;

fig. 9 is a schematic view of a battery pack according to an embodiment of the present application;

fig. 10 is a schematic view showing a partial structure of a battery pack according to an embodiment of the present application;

fig. 11 is a schematic view showing a partial structure of a battery pack according to an embodiment of the present application;

FIG. 12 is a schematic view of a film package and an over-temperature protection device according to an embodiment of the present application;

fig. 13 is a schematic view of a battery pack according to an embodiment of the present application;

Fig. 14 is a schematic view of a battery pack according to an embodiment of the present application;

fig. 15 is a schematic view of a battery pack according to an embodiment of the present application;

fig. 16 is a schematic view illustrating a structure of a battery pack according to an embodiment of the present application.

Detailed Description

The following description of the technical solutions according to the embodiments of the present application will be given with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, but not all embodiments.

The terms "first," "second," and the like herein are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, unless otherwise indicated, the meaning of "a plurality" is two or more.

Herein, unless expressly stated and limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact through an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

For convenience of understanding, the following explains and describes english abbreviations and related technical terms related to the embodiments of the application.

DCDC: DC, an abbreviation of Direct Current, means a device that converts a Direct Current power supply of a certain voltage level into a Direct Current power supply of another voltage level. DCDC is divided into a boost power supply and a buck power supply according to a voltage class conversion relationship, for example, a DCDC converter connected to a vehicle power supply system converts high-voltage direct current into low-voltage direct current.

NTC: negative Temperature Coefficient it refers to the phenomenon of thermistors and materials having a negative temperature coefficient, which decrease exponentially with increasing resistance to temperature.

The embodiment of the application provides a battery pack, which comprises a battery management unit and a plurality of single batteries, wherein the battery management unit comprises an over-temperature detection circuit and an over-temperature protection element, the over-temperature protection element is connected in series or in parallel in the over-temperature detection circuit, the over-temperature protection element is arranged on the surface of at least part of the single batteries in the plurality of single batteries, and the over-temperature detection circuit and the over-temperature protection element monitor the temperature of the surface of the single battery covered by the over-temperature protection element part. The over-temperature protection element is used for fusing when the temperature of any one of at least partial single batteries exceeds the melting point of the over-temperature protection element so as to disconnect the over-temperature detection circuit, the battery management unit is used for generating an over-temperature signal when the over-temperature detection circuit is disconnected, and the battery management unit is used for controlling the heat dissipation device to cool the battery pack according to the over-temperature signal. The battery pack provided by the embodiment of the application can more flexibly arrange the over-temperature protection element on the surface of the single battery, improves the sensitivity of over-temperature monitoring of the battery pack, and does not influence the normal operation of the battery pack when over-temperature fusing occurs because the over-temperature protection element is not directly connected with the single battery.

The battery pack provided by the embodiment of the application can be applied to a vehicle-mounted power supply system, wherein the vehicle-mounted power supply system comprising the battery pack can be applied to a vehicle.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a vehicle 1 according to an embodiment of the application. In one embodiment, the vehicle 1 includes a vehicle body 10 and an in-vehicle power supply system 2, the in-vehicle power supply system 2 being mounted on the vehicle body 10, the in-vehicle power supply system 2 supplying power to an in-vehicle load 20 through a battery pack 3.

In the present embodiment, the vehicle 1 is a wheeled vehicle that is driven or towed by a power unit, and that is used by a person traveling on a road or for transporting articles and performing works for special works. The Vehicle 1 includes an Electric Vehicle/Electric Vehicle (EV), a pure Electric Vehicle (Pure Electric Vehicle/BatteryElectric Vehicle, PEV/BEV), a hybrid Electric Vehicle (Hybrid Electric Vehicle, HEV), an extended range Electric Vehicle (Range Extended Electric Vehicle, REEV), a Plug-in hybrid Electric Vehicle (Plug-in Hybrid Electric Vehicle, PHEV), a new energy Vehicle (New Energy Vehicle), and the like. In some embodiments, the vehicle 1 includes a passenger car, various special work vehicles having specific functions, such as an engineering rescue vehicle, a sprinkler, a sewage suction vehicle, a cement mixer vehicle, a crane vehicle, a medical vehicle, and the like. The vehicle 1 may also be a robot that can travel.

In an embodiment, the vehicle 1 further comprises wheels 11, and the on-board power supply system 2 is capable of driving the wheels 11 to rotate. The number of wheels 11 of the vehicle 1 may be three or more, and the present application is not limited thereto.

Referring to fig. 2, fig. 2 is a schematic view of an application scenario of the vehicle-mounted power supply system 2 according to an embodiment of the present application, in an implementation manner, the vehicle-mounted power supply system 2 includes a vehicle-mounted load and a battery pack 3, and the battery pack 3 is used for supplying power to the vehicle-mounted load.

In this embodiment, the battery pack 3 is electrically connected to the vehicle load, and the battery pack 3 is used to meet the power demand of the normal operation of the vehicle load. Depending on the vehicle load, the dc voltage required by each vehicle load includes a high voltage dc power to supply power to the high voltage load, which illustratively includes the compressor 200, the seat heating module 210, the power system 220, etc., and a low voltage dc power to supply power to the low voltage load, which illustratively includes the dashboard, the control display, the lights, the USB interface, etc.

In an embodiment, the vehicle-mounted power supply system 2 can be charged by an external power supply, and electric energy is stored in the battery pack 3, so that when the vehicle-mounted load needs to be supplied with power, the electric energy stored in the battery pack 3 is released to supply power to the vehicle-mounted load.

In an embodiment, an On-board charger 21 (OBC) and a DCDC module 22 are disposed in the vehicle power supply system 2, where the On-board charger 21 is a functional module for charging the battery pack 3 from the ac power grid during parking, and the DCDC module 22 is a functional module for converting high-voltage dc into dc voltage required for operating the vehicle load, and the DCDC module 22 may supply power to the 12V vehicle load, for example.

In an embodiment, a battery management unit 300 (Battery Management Unit, BMU) is disposed on the battery pack 3, and the battery management unit 300 detects the temperature, voltage and current of the battery pack 3 in real time, and performs leakage detection, thermal management, battery equalization management, alarm reminding, calculation of the remaining capacity and discharge power, report of the battery degradation degree and the state of the remaining capacity, algorithmically control the maximum output power according to the temperature, voltage and current of the battery pack 3 to obtain the maximum driving mileage, algorithmically control the vehicle-mounted power supply to perform optimal current charging, and real-time communication with the vehicle-mounted overall controller, the motor controller, the energy control system, the vehicle-mounted display system, etc. through a bus interface.

In the existing vehicle-mounted power supply system 2, in order to achieve temperature monitoring of the battery pack 3, a thermistor such as an NTC is generally disposed on the surface of the unit battery, but when the thermistor is located at the position of the gap, the surface of the unit battery is easily damaged due to the hardness of the thermistor.

In the embodiment of the application, the over-temperature protection element is arranged in the battery pack 3, so that the over-temperature protection element is less limited when being arranged on the surface of the single battery, the sensitivity of over-temperature monitoring can be effectively improved, and the safety performance of the battery pack 3 and the vehicle-mounted power supply system 2 is improved.

Referring to fig. 3, fig. 3 is a schematic structural diagram of a power supply system 5 according to an embodiment of the present application, in which the power supply system 5 includes an energy storage system 4, the energy storage system 4 includes a converter 42 and a battery pack 3, and the converter 42 includes an AC/DC conversion circuit, wherein the AC/DC conversion circuit is used for being connected to both an external AC source 41 and the battery pack 3, and the AC/DC conversion circuit is used for converting AC power transmitted by the external AC source 41 into DC power and transmitting the DC power to the battery pack 3 for charging. In this embodiment, the battery pack 3 is used for storing energy, and when power supply to the dc load 44 is required, the battery pack 3 supplies power to the dc load 44.

In one embodiment, the converter 42 further comprises a DC/AC conversion circuit for converting the DC power transmitted by the battery pack 3 into AC power for powering the AC load 45.

In one embodiment, the external ac source 41 includes, but is not limited to, an ac grid, a fuel generator, or other ac source.

In one embodiment, the AC/DC conversion circuit may be a bidirectional conversion circuit, i.e., converting AC power to DC power, or converting DC power to AC power.

In one embodiment, the power supply system 5 further includes a photovoltaic module 43, the converter 42 includes a DC/DC conversion circuit, the photovoltaic module 43 is connected to the DC/DC conversion circuit, and the photovoltaic module 43 is connected to the battery pack 3 through the DC/DC conversion circuit and is used to charge the battery pack 3. The converter 42 integrates an AC/DC conversion circuit and a DC/DC conversion circuit, where the AC/DC conversion circuit is used to convert between AC and DC, and the DC/DC conversion circuit is used to convert between high-voltage and low-voltage DC. The battery pack 3 is charged with energy by the photovoltaic module 43, and the power supply system 5 may also be referred to as a photovoltaic power supply system.

In the present embodiment, the DC/DC conversion circuit is configured to convert the parameters of the direct current generated by the photovoltaic module 43 into parameters required for charging the battery pack 3, so as to improve the charging effect and the charging adaptation effect on the battery pack 3.

In one embodiment, the photovoltaic module 43 comprises at least one photovoltaic panel 401, the photovoltaic panel 401 being connected to a current transformer 42. In one embodiment, the photovoltaic module 43 includes a plurality of photovoltaic panels 401 connected in series, and dc power of the plurality of photovoltaic panels 401 is collected and connected to the inverter 42 by the series connection.

The battery pack 3 provided by the embodiment of the application is provided with the over-temperature protection element, and the over-temperature protection element is less limited when being arranged on the surface of the single battery, so that the sensitivity of over-temperature monitoring can be effectively improved, and the safety performance of the battery pack 3 and the energy storage system 4 is improved.

The battery pack 3 provided by the embodiment of the present application will be described in detail.

Referring to fig. 4, fig. 4 is a schematic structural diagram of a battery pack 3 according to an embodiment of the application, in an embodiment, the battery pack 3 includes a battery management unit 300 and a plurality of unit cells 400, the battery management unit 300 includes an over-temperature detection circuit 310 and an over-temperature protection element 320, and the over-temperature protection element 320 is connected in series or parallel to the over-temperature detection circuit 310. The over-temperature protection element 320 is disposed on a surface of at least a portion of the unit cells 400 among the plurality of unit cells 400, and the over-temperature protection element 320 is used to fuse when a temperature of any one of the at least a portion of the unit cells 400 exceeds a melting point of the over-temperature protection element 320, so that the over-temperature detection circuit 310 is turned off. The battery management unit 300 is used for generating an over-temperature signal when the over-temperature detection circuit 310 is turned off, and the battery management unit 300 is used for controlling the battery pack 3 to cool down according to the over-temperature signal.

The battery management unit 300 monitors and manages the battery pack 3, so as to protect the battery and improve the comprehensive performance of the battery. In this embodiment, the battery management unit 300 is configured to monitor the temperature of the unit battery 400, and when the battery management unit 300 generates an over-temperature signal, the battery management unit 300 takes emergency measures to regulate and control the temperature of the unit battery 400, so as to ensure that the battery pack 3 runs safely and stably.

In the present embodiment, the over-temperature protection element 320 is connected in series with the over-temperature detection circuit 310, or a part of the over-temperature protection element 320 is connected in series with the over-temperature detection circuit 310, a part of the over-temperature protection element 320 is connected in parallel with the over-temperature detection circuit 310, or the over-temperature protection element 320 is connected in parallel with the over-temperature detection circuit 310. When the temperature of the unit battery 400 increases to the melting point of the over-temperature protection element 320, the over-temperature protection element 320 fuses, so that the over-temperature detection circuit 310 is disconnected from the position in series or parallel with the over-temperature protection element 320, and the battery management unit 300 detects that the over-temperature detection circuit 310 generates a voltage change or a current change due to the fusing of the over-temperature protection element 320 and emits an over-temperature signal.

The single battery 400 includes a single battery housing and a pole core (not shown) located in the single battery housing, the pole core is electrically connected with an external bus component through a pole lug, and the single batteries 400 are connected in series or in parallel and then are connected in parallel through the bus component, so as to realize charging or discharging of the single batteries 400 through the bus component. In the present embodiment, there is no direct electrical connection between the overheat protection element 320 and the bus members of the unit cells 400. If the over-temperature protection element 320 is electrically connected between the bus member of the unit cell 400 and other devices, such as the battery management unit 300, when the over-temperature protection element 320 is over-temperature fused, the electrical connection between the unit cell 400 and the other devices is also disconnected, resulting in interruption of the charging or discharging operation of the battery pack 3, which affects the smooth operation of the in-vehicle power supply system 2. In the present embodiment, the over-temperature protection element 320 is only electrically connected to the over-temperature detection circuit 310 and the battery management unit 300, and after the over-temperature protection element 320 is melted down, the battery management unit 300 can cool the battery pack 3 through the heat dissipation device, so that the protection and the temperature control of the battery pack 3 are realized on the premise of not interrupting the normal charge or discharge of the battery pack 3. In an embodiment, the heat sink comprises an oil-cooled heat sink, a water-cooled heat sink, or an air-cooled heat sink. It should be noted that, in the embodiments of the present application, the connection includes an electrical connection relationship.

In the present embodiment, at least a part of the surfaces of the unit cells 400 among the plurality of unit cells 400 are provided with the over-temperature protection element 320, and the position of the over-temperature protection element 320 is the coverage area of temperature monitoring. In the prior art, a thermistor such as NTC is generally used to monitor the temperature of the battery pack, and the thermistor means that the resistance of the thermistor changes when the temperature changes, so that an over-temperature signal is emitted after the over-temperature detection circuit detects the change of the resistance, however, the thermistor has a hard texture, and the single battery can expand when in operation, so that the thermistor is difficult to be arranged at a gap in the battery pack 3. If the thermistor is disposed at the gap between the unit cells 400, when the plurality of unit cells 400 are pre-compressed under pressure, the harder thermistor may damage the case of the unit cell 400, and the thermistor may press the case of the unit cell 400 to damage the unit cell 400 when the unit cell is expanded while operating. The over-temperature protection element 320 provided in the battery management unit 300 according to the present embodiment may be provided on a plurality of surfaces in the unit battery 400, and the layout of the over-temperature protection element 320 is more flexible.

In this embodiment, the temperature of the normal operation of the unit battery 400 generally has a range, the melting point of the over-temperature protection element 320 may be located within the temperature range of the normal operation of the unit battery 400, when the over-temperature protection element 320 melts, an early warning signal may be sent to the battery management unit 300 in advance, and since the temperature of the unit battery 400 is still in the normal range at this time, the unit battery management unit 300 may more easily maintain the unit battery 400 in the normal operation state by adopting a cooling measure, and the over-temperature monitoring sensitivity is higher. In an embodiment, the melting point of the over-temperature protection element 320 may also be higher than the upper limit of the temperature range in which the unit cell 400 operates normally.

In the application, by arranging the over-temperature protection element 320 in the battery pack 3, and fusing the over-temperature protection element 320 when the temperature rises to the melting point, the over-temperature detection circuit 310 is disconnected, thereby promoting the battery management unit 300 to generate an over-temperature signal, realizing the temperature control of the single battery 400, being beneficial to improving the safety performance of the battery pack 3 and ensuring that the vehicle-mounted power supply system 2 or the energy storage system 4 works in a stable state.

Second, compared with the thermistor, the over-temperature protection element 320 is convenient to flexibly arrange the over-temperature protection element 320 on different surfaces or gaps of the single battery 400, and when the over-temperature protection element 320 is extruded, the over-temperature protection element 320 is not easy to damage the surface of the over-temperature protection element 320 and the surface of the single battery 400 where the over-temperature protection element is arranged.

Thirdly, there is no electrical connection relationship between the over-temperature protection element 320 and the converging parts of the single battery 400, even if the over-temperature protection element 320 is fused, the electrical connection between the converging parts of the single battery 400 and other devices is not broken, after the battery management unit 300 takes measures to cool the single battery 400, the single battery 400 can work normally without re-establishing the electrical connection between the single battery 400 and other devices, so that the operation cost can be reduced, and the stable operation of the battery pack 3 and the vehicle-mounted power supply system 2 is guaranteed.

In one embodiment, the battery pack 3 includes a battery pack case and a circuit board (not shown), and the battery management unit 300 and the plurality of unit cells 400 are located in the battery pack case. Wherein the battery management unit 300 is integrated on a circuit board that is positioned on top of the plurality of unit cells. In one embodiment, other circuitry for controlling the transmission of battery pack signals or the communication of battery packs is also integrated on the circuit board.

Referring to fig. 3, fig. 5 and fig. 6 in combination, fig. 5 is a schematic structural diagram of a battery pack 3 according to an embodiment of the present application, and fig. 6 is a schematic structural diagram of a battery pack 3 according to an embodiment of the present application, in which an extension path of the overtemperature protection element 320 is a straight line or a curved line (shown in fig. 3, fig. 5 and fig. 6 in combination). When the extending path of the over-temperature protection element 320 is curved (as shown in fig. 5 and 6), the distribution position of the over-temperature protection element 320 on the unit cell 400 is increased, so as to improve the temperature monitoring accuracy of the unit cell 400.

In an embodiment, the over-temperature protection element 320 is configured as a straight line, so as to reduce the operation difficulty and cost, wherein the extending direction of the straight line may be the first direction X (as shown in fig. 3), or a direction intersecting the first direction X and perpendicular to the height direction Y of the unit cell 400.

In the embodiment shown in fig. 5 and 6, the over-temperature protection element 320 is configured to be curved, so as to facilitate the expansion of the over-temperature detection range, where the over-temperature protection element 320 may be curved on the surface of each unit cell 400 (as shown in fig. 5), and at this time, the over-temperature protection element 320 can perform temperature monitoring on different positions of each unit cell 400. Alternatively, the over-temperature protection element 320 is curved on the entire surface of the unit battery pack 410 (as shown in fig. 6), and at this time, the over-temperature protection element 320 can monitor the temperature of different positions of the entire surface of the unit battery pack 410, so that the battery management unit 300 can take countermeasures for the over-temperature of the battery more timely.

In one embodiment, the melting point of the over-temperature protection element 320 is higher than the highest temperature of the unit cell 400 when it is operating normally.

In this embodiment, a range is generally present for the temperature of the unit cell 400 to meet the normal operation, and the melting point of the over-temperature protection element 320 is higher than the upper limit of the temperature range, so that the battery management unit 300 only generates an over-temperature signal when the unit cell 400 is in an over-temperature state, and further cools and dissipates heat to the battery pack 3, so the scheme is beneficial to avoiding frequent generation of the over-temperature signal by the battery management unit 300 and reducing the cost of over-temperature detection.

Exemplary, the temperature of the unit cell 400 in normal operation is greater than or equal to 70 ℃ and less than or equal to 120 ℃. I.e., the upper limit temperature of the unit cell 400 at the time of operation is 120 c. At this time, the melting point of the over-temperature protection element 320 is greater than 120 ℃, and the melting point of the over-temperature protection element 320 is 125 ℃ as an example. When the working temperature of the single battery 400 reaches 125 ℃, the melting point of the over-temperature protection element 320 is reached, the over-temperature protection element 320 is fused, the over-temperature detection circuit 310 is disconnected, and when the battery management unit 300 detects that the over-temperature detection circuit 310 is disconnected, an over-temperature signal is sent out to control the cooling system to cool the battery pack 3 so as to protect the battery pack 3.

In an embodiment, the melting point of the over-temperature protection element 320 is between the lower limit temperature and the upper limit temperature when the unit battery 400 is operating normally, and the melting point of the over-temperature protection element 320 is greater than the optimal operating temperature of the unit battery 400. The optimal operating temperature of the unit cells 400 refers to a temperature at which charge and discharge with high efficiency can be maintained, and specific values can be determined according to the unit cells 400 or the unit cell packs 3.

For example, the temperature of the unit cell 400 in normal operation is greater than or equal to 70 ℃ and less than or equal to 120 ℃. That is, the upper limit temperature of the unit cell 400 is 120 ℃ and the lower limit temperature is 70 ℃ when it is operated. The optimum operating temperature of the unit cell 400 is 80 deg.c. Illustratively, the melting point of the overtemperature protection element 320 has a value of 85 ℃. When the working temperature of the single battery 400 rises to 85 ℃, the melting point of the over-temperature protection element 320 is reached, the over-temperature protection element 320 is fused, the over-temperature detection circuit 310 is disconnected, the battery management unit 300 sends out an over-temperature signal when detecting that the over-temperature detection circuit 310 is disconnected, and the cooling system is controlled to cool the battery pack 3 so as to protect the battery pack 3, so that the battery pack 3 can work around the optimal working temperature, the battery pack 3 can be kept in the optimal working state, and the working efficiency of the battery pack 3 is improved.

In one embodiment, the overtemperature protection element 320 is an alloy sheet or a metal sheet. The melting point of the alloy sheet is greater than or equal to 70 ℃ and less than or equal to 120 ℃, and the melting point of the metal sheet is greater than or equal to 70 ℃ and less than or equal to 120 ℃. In the present embodiment, the alloy sheet and the metal sheet have low melting points, and melt when the temperature exceeds the melting points, and the alloy sheet and the metal sheet each have conductivity, so that the conditions for connection to the overheat detection circuit 310 and the battery management unit 300 can be satisfied. Illustratively, the overtemperature protection element 320 is a binary, ternary or quaternary eutectic alloy with a proportion of bismuth, cadmium, tin, lead, dysprosium, indium, etc. elements as the main components, or the overtemperature protection element 320 includes, but is not limited to, any one of bismuth, cadmium, tin, lead, dysprosium, indium. The specific composition of the alloy sheet and the metal sheet is not limited in the present application, and those skilled in the art can adjust according to actual needs.

Referring to fig. 7, fig. 7 is a schematic structural diagram of a battery pack 3 according to an embodiment of the present application, in an embodiment, an over-temperature protection element 320 includes a plurality of over-temperature protection sub-elements 3200 disposed at intervals along an extending direction of the over-temperature protection element 320, two adjacent over-temperature protection sub-elements 3200 are connected by a conductive member 3100, and the plurality of over-temperature protection sub-elements 3200 are disposed on at least a portion of surfaces of the plurality of unit batteries 400. For monitoring the temperature of at least a portion of the unit cells 400, and can reduce costs.

In the present embodiment, the over-temperature protection sub-elements 3200 and the conductive members 3100 are alternately arranged in the extending direction of the over-temperature protection element 320, and the portion of the over-temperature protection element 320 where the over-temperature protection sub-element 3200 is arranged can perform over-temperature protection on the operating temperature of the unit cells 400, and can perform over-temperature monitoring on at least part of the unit cells 400 in the plurality of unit cells 400 on the premise of minimizing the manufacturing cost of the over-temperature protection element 320. The connection relationship between two adjacent over-temperature protection sub-elements 3200 includes electrical connection, so that even if a plurality of over-temperature protection sub-elements 3200 are arranged at intervals, when any one of the over-temperature protection sub-elements 3200 is fused, the over-temperature detection circuit 310 is disconnected, and no influence is caused on the monitoring over-temperature phenomenon of the over-temperature protection element 320.

In this embodiment, the conductive member 3100 may be a copper wire or a low-cost conductive cable. In other embodiments, the two over-temperature protection sub-elements 3200 are connected by a copper bar.

In one embodiment, the overtemperature protection sub-element 3200 is an alloy block or a metal block.

In one embodiment, the alloy in the alloy block is a binary, ternary or quaternary eutectic alloy with bismuth, cadmium, tin, lead, dysprosium, indium and other elements in a certain proportion as main components.

In one embodiment, the metal in the metal block is made of any one of bismuth, cadmium, tin, lead, dysprosium and indium.

In one embodiment, the melting point of the alloy or metal block is greater than or equal to 70 ℃ and less than or equal to 120 ℃.

In an embodiment, a plurality of over-temperature protection sub-elements 3200 are arranged on a surface of each of the plurality of unit cells 400. This solution is advantageous for further improving the temperature monitoring capability of the over-temperature protection sub-element 3200.

Referring to fig. 8, fig. 8 is a schematic structural diagram of a battery pack 3 according to an embodiment of the application, in an embodiment, a battery management unit 300 includes a plurality of over-temperature protection elements 320, wherein melting points of the plurality of over-temperature protection elements 320 are different, and the plurality of over-temperature protection elements 320 are distributed at different positions of a plurality of unit batteries 400. For monitoring the operating temperature of the unit cell 400.

In the present embodiment, the plurality of over-temperature protection elements 320 are connected to the over-temperature detection circuit 310 and the battery management unit 300, and when any one of the plurality of over-temperature protection elements 320 is fused, the over-temperature detection circuit 310 is turned off, and the battery management unit 300 generates an over-temperature signal.

In the present embodiment, the operating temperatures of the different locations of the unit cell 400 are different, and the larger the volume of the unit cell 400, the larger the temperature difference between the different locations of the unit cell 400. The over-temperature protection elements 320 having different melting points are disposed at different positions of the unit cells 400, and the melting points of the over-temperature protection elements 320 correspond to the temperatures of the different positions of the unit cells 400. By disposing the overtemperature protection element 320 with a higher melting point at a position where the temperature of the single battery 400 is higher, and disposing the overtemperature protection element 320 with a lower melting point at a position where the temperature of the single battery 400 is lower, it is possible to avoid both extreme cases that the overtemperature protection element 320 is fused when the temperature is lower and that the overtemperature protection element 320 is not fused when the temperature is higher. The over-temperature protection elements 320 with different melting points are combined to play a role in multi-level over-temperature monitoring, so that the accuracy and the sensitivity of the over-temperature protection elements 320 for monitoring over-temperature phenomena are improved.

Illustratively, in the embodiment shown in fig. 8, the battery management unit 300 includes two over-temperature protection elements 320, and the two over-temperature protection elements 320 are respectively denoted as an over-temperature protection element 320a and an over-temperature protection element 320b, and the melting point of the over-temperature protection element 320a is higher than the melting point of the over-temperature protection element 320 b. The battery pack 3 includes two sets of battery packs 410, each set of battery packs 410 includes a plurality of battery cells 400 arranged along a first direction X, and the two sets of battery packs 410 are arranged side by side along a second direction Y, where the first direction X and the second direction Y are perpendicular to each other and are perpendicular to a height direction Z of the battery pack 3, and the height direction Z of the battery pack 3 is also the height direction of the battery pack 400. In this embodiment, the overheat protection element 320a with a higher melting point is disposed at an adjacent middle position in the two sets of unit battery packs 410, and the overheat protection element 320b with a lower melting point is disposed at a position far from the middle in the two sets of unit battery packs 410, so that the overheat protection element 320a and the overheat protection element 320b can monitor the temperature of the battery pack 3 more accurately.

With continued reference to fig. 8, in one embodiment, an overtemperature protection element 320 is disposed on a surface of each of the plurality of cells 400. For monitoring the operating temperature of each unit cell 400, and improving the detection sensitivity of the battery pack 3.

In this embodiment, the monitoring range of the over-temperature protection element 320 covers the surface of each of the plurality of unit cells 400, so that over-temperature detection can be implemented on all of the unit cells 400 in the battery pack 3, the monitoring sensitivity of the over-temperature protection element 320 to the battery pack 3 is further improved, and the over-temperature protection element 320 is connected with the over-temperature detection circuit 310 and the battery management unit 300, so that the battery management unit 300 can implement temperature control on each of the plurality of unit cells 400, and the working efficiency of the battery pack 3 is improved.

Referring to fig. 9, fig. 9 is a schematic structural diagram of a battery pack 3 according to an embodiment of the application, and in an embodiment, at least some of the unit cells 400 are arranged adjacent to each other in sequence. The battery management unit 300 includes a plurality of over-temperature protection elements 320, and at least one over-temperature protection element 320 is disposed between sides of two unit batteries 400 that are adjacently disposed. So that the overheat protection element 320 can detect the temperatures of the adjacent sides 420 of the adjacent two unit batteries 400.

In the present embodiment, at least some of the plurality of unit cells 400 are arranged along the first direction X, and in order to make the battery pack 3 more compact, the gaps between the two opposite side surfaces 420 of the plurality of unit cells 400 are generally smaller, and it is not suitable to provide a hard thermistor at the gaps. Since the over-temperature protection element 320 is fused when the temperature rises, when the over-temperature protection element 320 is disposed on the adjacent side 420 of the two unit batteries 400, the surface of the unit batteries 400 is not extruded or damaged, and the stability and the service life of the over-temperature protection element 320 and the unit batteries 400 are improved.

In this embodiment, the plurality of over-temperature protection elements 320 are disposed on different surfaces of the unit battery 400, which is beneficial to expanding the monitoring range of the over-temperature protection elements 320 for the over-temperature phenomenon and improving the detection sensitivity.

In an embodiment, at least some of the plurality of unit cells 400 form a unit cell group 410, and in the unit cell group 410, the plurality of unit cells 400 are arranged along the first direction X.

In an embodiment, each of the plurality of over-temperature protection elements 320 is disposed between sides of two unit cells 400 adjacently disposed in the unit cell group 410. This solution is advantageous for improving the monitoring sensitivity of the over-temperature protection element 320 to the temperature of the side 420 of the unit cell 400.

In an embodiment, part of the unit cells 400 are adjacently arranged along the second direction Y, and the over-temperature protection element 320 is located between the side surfaces of the two unit cells 400 arranged along the second direction Y.

In one embodiment, the overtemperature protection element 320 is in the form of a sheet. The thickness of the over-temperature protection element 320 of the sheet structure is thin, and when placed between the sides of the adjacent two unit cells 400, the side case is not damaged when pressed by pressure.

Referring to fig. 10, fig. 10 is a schematic view of a partial structure of a battery pack 3 according to an embodiment of the present application, in which the battery pack 3 further includes a film package 500, the film package 500 includes a first film 510 and a second film 520 stacked together, the over-temperature protection element 320 is located between the first film 510 and the second film 520, and a cavity 530 is provided between the over-temperature protection element 320 and at least one of the first film 510 and the second film 520, and the cavity 530 is used for accommodating a molten mass melted at a fusing point in the over-temperature protection element 320. So that the molten mass is separated from the non-melted portion of the over-temperature protection element 320, thereby enhancing the fusing effect.

In the present embodiment, the film package 500 serves to insulate the over-temperature protection element 320 from the unit cell 400 and to facilitate installation of the over-temperature protection element 320. Illustratively, the first film 510 and the second film 520 in the film package 500 are made of a material such as silicone or resin, and the over-temperature protection element 320 is packaged between the first film 510 and the second film 520 by hot pressing. Illustratively, the resin may be a polyimide film. The first film 510, the over-temperature protection element 320, and the second film 520 are stacked, wherein the cavity 530 is disposed between the surface of the over-temperature protection element 320 facing the first film 510 and the first film 510, or between the surface of the over-temperature protection element 320 facing the second film 520 and the second film 520. In the embodiment shown in fig. 10, the first thin film 510 and the second thin film 520 are arranged along the height direction Z of the unit cell 400, and the second thin film 520 has a cavity 530, so that the molten mass falls into the cavity 530 under the action of gravity to be separated from the non-melted portion of the over-temperature protection element 320, and the breaking process of the over-temperature detection circuit 310 is accelerated, thereby improving the over-temperature detection efficiency of the battery management unit 300. In addition, the over-temperature protection element 320 is integrated into the film package 500, so that the over-temperature protection element 320 is more convenient to replace after being fused.

In one embodiment, the cavity 530 is a groove formed on a surface of the first film 510 or the second film 520 facing the over-temperature protection element 320, and the groove is used for accommodating the molten mass after the over-temperature protection element 320 is melted. As shown in fig. 10, the cavity 530 is a groove of the surface of the second film 520 facing the over-temperature protection element 320.

In one embodiment, the sum of the thicknesses of the film package 500 and the over-temperature protection element 320 is smaller than the gap width between two adjacent unit cells 400.

Referring to fig. 11, fig. 11 is a schematic view of a partial structure of a battery pack 3 according to an embodiment of the application, in an embodiment, a surface of an overtemperature protection element 320 away from a second film 520 is fixed to a first film 510 through a first adhesive layer 540, a surface of the overtemperature protection element 320 away from the first film 510 is fixed to the second film 520 through a second adhesive layer 550, through holes 560 penetrating through two opposite surfaces of the second adhesive layer 550 are formed in the second adhesive layer 550, and the through holes 560 form cavities 530. For receiving the portion of the overtemperature protection element 320 that is melted.

In the present embodiment, the first adhesive layer 540 is used for reinforcing the fixed connection relationship between the over-temperature protection element 320 and the first film 510, and the second adhesive layer 550 is used for reinforcing the fixed connection relationship between the over-temperature protection element 320 and the second film 520. The first thin layer, the first adhesive layer 540, the over-temperature protection element 320, the second adhesive layer 550, and the second thin film 520 are sequentially stacked in the height direction Y of the unit cell 400.

In the embodiment shown in fig. 11, a portion of the overtemperature protection element 320 located between the first adhesive layer 540 and the second adhesive layer 550 is an alloy sheet, and the other portion is a conductive member, wherein the portion corresponding to the through hole 560 is an alloy sheet, so that the melted alloy sheet falls into the through hole 560 after being melted. This solution is advantageous in reducing the manufacturing costs of the overtemperature protection element 320. In another embodiment, the components located between the first adhesive layer 540 and the second adhesive layer 550 are all over-temperature protection elements 320. This solution is advantageous for improving the detection sensitivity of the overtemperature protection element 320.

Referring to fig. 12, fig. 12 is a schematic structural diagram of a film package 500 and an over-temperature protection element 320 according to an embodiment of the application, and fig. 13 is a schematic structural diagram of a battery pack according to an embodiment of the application. In the present embodiment, the film package 500 has a sheet shape, and the over-temperature protection element 320 has a "U" shape (as shown in fig. 12). In which the film package 500 covers the plurality of unit cells 400 (as shown in fig. 12), in the present embodiment, the battery pack 3 includes at least two sets of unit cell groups 410, and the film package 500 covers at least two sets of unit cell groups 410 (as shown in fig. 13). In the present embodiment, by arranging the thin film package 500 in a sheet shape such that the over-temperature protection element 320 and the thin film package 500 are integrally modularized, not only can a plurality of unit cells 400 be monitored at the same time, but also assembly is facilitated.

In the embodiment shown in fig. 13, a sheet-like film package 500 is provided on the top surface of the unit cell 400. In some embodiments, the sheet-shaped thin film package 500 may be disposed on the side surfaces of two adjacent unit cells 400, and the sheet-shaped thin film package 500 does not cause backlog on the side surfaces of the unit cells 400.

Referring to fig. 14, fig. 14 is a schematic structural diagram of a battery pack according to an embodiment of the application. In this embodiment, the thin film package 500 is in a strip shape, and the shape of the over-temperature protection element 320 is also in a strip shape matching the thin film package 500. In the embodiment shown in fig. 14, the battery pack 3 includes at least two groups of unit battery packs 410 and a plurality of film packages 500, each of the film packages 500 is provided with an over-temperature protection element 320 therein, and one of the film packages 500 covers one of the unit battery packs 410. In fig. 14, it is shown that the over-temperature protection elements 320 in the two film packages 500 are respectively used to monitor a group of unit battery packs 410. The thin film package 500 in a strip shape occupies a small area, saves cost, and is flexible in arrangement mode.

In some embodiments, the shape of the film package 500 is not limited to the above-described sheet and strip, but may be triangular, circular, etc., and the over-temperature protection element 320 matched thereto may be provided in a triangular, circular, etc.

Referring to fig. 15, fig. 15 is a schematic structural diagram of a battery pack 3 according to an embodiment of the application. In one embodiment, the film package 500 includes a cell voltage sampling circuit 570, the cell voltage sampling circuit 570 is located between the first film 510 and the second film 520 (not shown), and the cell voltage sampling circuit 570 is spaced apart from the over-temperature protection element 320. The cell voltage sampling circuit 570 and the over-temperature protection element 320 are integrated in the thin film package 500, such that the thin film package 500 is capable of monitoring both the voltage within the cell 400 and the temperature of the cell 400.

In the present embodiment, the cell voltage sampling circuit 570 is connected to the unit cell 400 and the battery management unit 300, and the cell voltage sampling circuit 570 can determine whether or not there is an overcharge or overdischarge in the battery pack 3 by monitoring the voltage of the unit cell 400, thereby avoiding a safety accident. The cell voltage sampling circuit 570 obtains abnormal voltage information and transmits the voltage information to the battery management unit 300, and the battery management unit 300 generates a corresponding signal to solve the abnormal situation. The connection relationship between the battery cell voltage sampling circuit 570 and the battery management unit 300 may be an electrical connection, for transmitting voltage information.

In this embodiment, the cell voltage sampling circuit 570 and the over-temperature detection circuit 310 are disposed at intervals in the thin film package 500, so that they are independent of each other and do not affect each other. The battery cell voltage sampling circuit 570 and the over-temperature detection circuit 310 are integrated into the thin film package 500, so that the installation and operation of the battery cell voltage sampling circuit and the over-temperature detection circuit 310 are more convenient, and the integration level of the battery management unit 300 is higher.

In one embodiment, the assembly of the thin film package 500, the cell voltage sampling circuit 570 and the over-temperature protection element 320 may also be referred to as a flexible circuit board.

In one embodiment, the battery pack 3 includes a flexible circuit board including the film package 500 and the cell voltage sampling circuit 570. Wherein the over-temperature protection element 320 is integrated in the flexible circuit board.

It should be noted that, fig. 15 only schematically illustrates the arrangement of the cell voltage sampling circuit 570 and the over-temperature protection element 320 in the thin film package 500, and does not represent the specific structure, dimension and positional relationship thereof, and those skilled in the art can adjust the arrangement according to the implementation requirement, so long as the cell voltage sampling circuit 570 and the over-temperature protection element 320 are ensured to be independent from each other.

Referring to fig. 16, fig. 16 is a schematic structural diagram of a battery pack 3 according to an embodiment of the application, in an embodiment, a surface of a unit cell 400 includes a top surface 430 and a bottom surface 440 opposite to each other along a height direction Y of the unit cell 400, the battery pack 3 includes a heat dissipating device 600 located on the bottom surface 440, and an over-temperature protection element 320 is located between the bottom surface 440 and the heat dissipating device 600. For monitoring the temperature of the bottom surface 440 of the battery pack 3.

In the present embodiment, the bottom surface 440 of the unit cell 400, the overheat protection element 320, and the heat sink 600 are stacked in the height direction Y of the unit cell 400. The heat dissipation device 600 is communicated with an external cooling system, when the battery management unit 300 transmits an over-temperature signal to the cooling system, the battery management unit 300 is indicated to monitor that the temperature of the bottom surface 440 of the single battery 400 is too high, the cooling system adjusts the properties of the cooling medium such as the flow rate, the temperature and the flow rate of the cooling medium in the heat dissipation device 600 according to the over-temperature signal, the heat dissipation effect of the cooling medium on the single battery 400 is improved, the battery pack 3 is restored to a normal working state again, and the battery management unit 300 is matched with the heat dissipation device 600, so that the problem of overheat of the battery is solved in time. In an embodiment, the cooling medium in the heat sink 600 may be water or oil. In an embodiment, if the over-temperature protection element 320 is replaced with a thermistor, the gap between the unit cell 400 and the heat sink 600 is very small, so that the temperature monitoring of the bottom surface 440 of the unit cell 400 cannot be achieved.

With continued reference to fig. 16, in one embodiment, a side of the heat dissipating device 600 facing the unit battery 400 is provided with a mounting hole 610 and a receiving groove 620, the mounting hole 610 is communicated with the receiving groove 620, and the mounting hole 610 is located between the bottom surface 440 of the unit battery 400 and the receiving groove 620. The over-temperature protection element 320 is located in the mounting hole 610, and the accommodating groove 620 is used for accommodating the molten body after the fusing part in the over-temperature protection element 320 is melted, so that the molten body is separated from the over-temperature protection element 320 at the non-fused part, and the fusing effect is improved.

In this embodiment, the mounting hole 610 is communicated with the receiving groove 620 along the height direction Y of the unit battery 400, so that the molten mass falls into the cavity 530 under the action of gravity and is separated from the unmelted part of the overtemperature protection element 320, and the disconnection process of the overtemperature detection circuit 310 is accelerated, thereby improving the overtemperature detection efficiency of the battery management unit 300.

In an embodiment, the two ends of the accommodating groove 620 along the first direction X are provided with supporting portions 6200, and the two ends of the over-temperature protection element 320 along the first direction X are located at the supporting portions 6200, where the supporting portions 6200 are used to prevent the over-temperature protection element 320 from falling into the accommodating groove 620 from the mounting hole 610 when not melted.

The battery pack, the vehicle, the energy storage system and the power supply system provided by the embodiment of the application are described in detail, and specific examples are applied to the principle and the embodiment of the application, and the description of the embodiment is only used for helping to understand the method and the core idea of the application; meanwhile, as those skilled in the art will have variations in specific embodiments and application scope in light of the ideas of the present application, the present description should not be construed as limiting the present application.

Claims

1. The battery pack is characterized by comprising a battery management unit and a plurality of single batteries, wherein the battery management unit comprises an over-temperature detection circuit and an over-temperature protection element, the over-temperature protection element is connected in series or in parallel in the over-temperature detection circuit, the over-temperature protection element is arranged on the surface of at least part of the single batteries, the over-temperature protection element is used for fusing when the temperature of any one of the at least part of the single batteries exceeds the melting point of the over-temperature protection element so as to disconnect the over-temperature detection circuit, the battery management unit is used for generating an over-temperature signal when the over-temperature detection circuit is disconnected, and the battery management unit is used for controlling the battery pack to cool according to the over-temperature signal.

2. The battery pack according to claim 1, wherein the extending path of the overtemperature protection element is a straight line or a curved line.

3. The battery pack according to claim 1 or 2, wherein the overtemperature protection element is an alloy sheet or a metal sheet, the alloy sheet has a melting point value of 70 ℃ or higher and 120 ℃ or lower, and the metal sheet has a melting point value of 70 ℃ or higher and 120 ℃ or lower.

4. A battery pack according to any one of claims 1 to 3, wherein the over-temperature protection element includes a plurality of over-temperature protection sub-elements arranged at intervals in the extending direction of the over-temperature protection element, and two adjacent over-temperature protection sub-elements are electrically connected by a conductive member, and the plurality of over-temperature protection sub-elements are arranged on the surface of at least part of the plurality of unit batteries.

5. The battery pack according to any one of claims 1 to 4, wherein the battery management unit includes a plurality of over-temperature protection elements having different melting points, the plurality of over-temperature protection elements being distributed at different positions of the plurality of unit cells.

6. The battery pack according to any one of claims 1 to 5, wherein the over-temperature protection element is arranged on a surface of each of the plurality of unit cells.

7. The battery pack according to any one of claims 1 to 5, wherein at least some of the unit cells of the plurality of unit cells are arranged adjacent to each other in order; the battery management unit includes a plurality of over-temperature protection elements, at least one of which is disposed between sides of two unit batteries that are adjacently disposed.

8. The battery pack of any one of claims 1-7, further comprising a film package comprising a first film and a second film in a stacked arrangement, the overtemperature protection element being positioned between the first film and the second film, a cavity being provided between the overtemperature protection element and at least one of the first film and the second film, the cavity for receiving a melt at a fuse in the overtemperature protection element.

9. The battery pack according to claim 8, wherein the surface of the overtemperature protection element away from the second film is fixed with the first film through a first adhesive layer, the surface of the overtemperature protection element away from the first film is fixed with the second film through a second adhesive layer, through holes penetrating through two opposite surfaces of the second adhesive layer are formed in the second adhesive layer, and the through holes form the cavity.

10. The battery pack of claim 8 or 9, wherein the film package includes a cell voltage sampling circuit located between the first film and the second film and spaced apart from the overtemperature protection element.

11. The battery pack of any one of claims 1-7, wherein the battery pack includes a heat sink located on a bottom surface of the cell, and the overtemperature protection element is located between the bottom surface of the cell and the heat sink.

12. The battery pack according to claim 11, wherein a side of the heat sink facing the unit battery is provided with a mounting hole and a receiving groove, the mounting hole and the receiving groove are communicated, and the mounting hole is located between a bottom surface of the unit battery and the receiving groove;

the over-temperature protection element is positioned in the mounting hole, and the accommodating groove is used for accommodating the molten body after the fusing part in the over-temperature protection element is fused.

13. A vehicle comprising a vehicle body and a battery pack according to any one of claims 1 to 12, the battery pack being mounted to the vehicle body.

14. An energy storage system comprising a current transformer and a battery pack according to any one of claims 1 to 12, the current transformer comprising an AC/DC conversion circuit, wherein the AC/DC conversion circuit is configured to be connected to an external AC source and the battery pack, the AC/DC conversion circuit being configured to convert AC power transmitted by the external AC source into DC power and to transmit the DC power to charge the battery pack.

15. A power supply system, wherein the power supply system comprises a photovoltaic module and the energy storage system of claim 14, the converter further comprises a DC/DC conversion circuit, the photovoltaic module is connected with the DC/DC conversion circuit, and the photovoltaic module is connected with the battery pack through the DC/DC conversion circuit and is used for charging the battery pack.