Battery pack, preparation method thereof and degumming detection method

Abstract

The invention relates to a battery pack, a preparation method thereof and a degumming detection method. The battery pack comprises a box body, a battery cell group, a heat-conducting structural adhesive, a cold plate, a flexible part and a charging part, wherein the battery cell group, the heat-conducting structural adhesive and the cold plate are sequentially stacked in the Z direction. The box body comprises a bottom protection plate, and the Z direction is the thickness direction of the bottom protection plate. The flexible part is arranged on the bottom protection plate and supported on the side, away from the heat conduction structural adhesive, of the cold plate. And in the Z direction, the projection of the flexible part is overlapped with the projection of the battery cell group, a cavity is formed in the flexible part, fluid is loaded in the cavity, and the flexible part is constructed to be capable of expanding and shrinking along with the change of the fluid content in the cavity so as to adjust the supporting force of the flexible part acting on the cold plate. The filling piece is communicated with the cavity and can allow fluid to enter and exit from the cavity so as to control the content of the fluid in the flexible piece. According to the technical scheme, the thermal management effect of the battery pack can be improved, whether the battery pack is degummed or not in the use process can be monitored, and the use reliability of the battery pack is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery pack and a preparation method thereof, and a debonding detection method. Background Art

[0002] A battery pack usually includes a box, multiple battery cell groups inside the box, and a cold plate. The cold plate exchanges heat with the battery cell group to achieve thermal management of the battery pack. Taking into account factors such as the cell size tolerance and the cell stacking tolerance, a downward pressure mechanism is usually used to apply a certain downward pressure to the battery cell group during the battery pack assembly process to ensure that it can be smoothly loaded into the box. When pressure is applied to the battery cell group, the cold plate at the bottom of the battery pack is squeezed by the battery cell group and is prone to local concavity, resulting in uneven thickness of the thermal conductive structural adhesive filled between the cold plate and the battery cell group, affecting the thermal management effect of the battery pack. Summary of the invention

[0003] Based on this, it is necessary to provide a battery pack and its preparation method, and a debonding detection method to address the problem that the thickness of the thermally conductive structural adhesive between the cold plate and the battery cell group is uneven, which affects the thermal management effect of the battery pack.

[0004] In a first aspect, the present application provides a battery pack, comprising: The box body, including the bottom guard plate; A battery cell group, a thermally conductive structural adhesive and a cold plate are sequentially stacked along a Z direction, wherein the Z direction is a thickness direction of the bottom guard plate; and A flexible member is provided on the bottom guard plate and supported on a side of the cold plate away from the thermally conductive structural adhesive; along the Z direction, the projection of the flexible member overlaps with the projection of the battery cell group, a cavity is configured inside the flexible member, a fluid is loaded in the cavity, and the flexible member is configured to expand and contract with changes in the fluid content in the cavity to adjust the supporting force of the flexible member on the cold plate; and A filling piece is communicated with the cavity and can allow the fluid to enter and exit the cavity so as to control the content of the fluid in the flexible piece.

[0005] In some embodiments, the flexible member and the battery cell group are both configured in plurality; in the Z direction, the flexible member is arranged one by one in each battery cell group; There are multiple filling pieces, and the cavity of each flexible piece is independently connected to one of the filling pieces via a pipeline.

[0006] In some embodiments, the flexible member comprises an elastically expandable support frame, and the cold plate is supported on the support frame; The cavity is located in the support frame, and the support frame has an initial volume. When the fluid causes the volume of the cavity to exceed the initial volume, the support frame is squeezed by the fluid to expand and increase its volume.

[0007] In some embodiments, the flexible member further includes an elastic bladder forming the cavity, and the elastic bladder is located within the support frame; the volume of the elastic bladder can change with the content of the fluid inside, and when the fluid causes the volume of the elastic bladder to exceed the initial volume, the support frame is squeezed by the elastic bladder and expands to increase its volume.

[0008] In some embodiments, a plurality of the elastic bladders are arranged in the support frame, and all the elastic bladders are sequentially separated and arranged along the X direction, where the X direction is the length direction of the bottom guard plate.

[0009] In some embodiments, each of the elastic bladders within the same support frame is independently connected to the filling member via a pipeline.

[0010] In some embodiments, the support frame includes a partition portion, and the partition portion is separated between adjacent elastic bladders; The partition portion includes a partition groove recessed in the outer surface of the support frame, and the partition groove extends along the Y direction intersecting the X direction, where the Y direction is the width direction of the bottom guard plate.

[0011] In some embodiments, the battery cell group includes an explosion-proof valve, and the explosion-proof valve is located on one side of the battery cell group facing the cold plate along the Z direction, and the thermally conductive structural adhesive avoids the explosion-proof valve; The cold plate is provided with an avoidance portion, and the flexible member is provided with a thinning portion, and the explosion-proof valve, the avoidance portion, and the thinning portion are arranged corresponding to each other along the Z direction; the avoidance portion and the thinning portion are configured to be able to allow the high-temperature and high-pressure flue gas released when the explosion-proof valve relieves pressure to flow through. The fluid filled in the cavity includes a fire extinguishing substance, and the thinning portion allows the high-temperature and high-pressure flue gas to enter the cavity to be cooled by the fire extinguishing substance.

[0012] In some embodiments, the filling member includes a valve body, a core body, a thimble, and a sealing plug. The valve body has a through hole, and the core body, the thimble, and the sealing plug are all arranged in the through hole; A core cavity is provided in the core body, the thimble penetrates through the core cavity, and is movably arranged relative to the core body in the depth direction of the through hole; The sealing plug is fixed to the thimble and can open and close the core cavity when moving with the thimble.

[0013] In some embodiments, the battery pack further includes a monitoring device and a pressure detection member. The pressure detection member is used to determine the supporting force provided by the fluid in the cavity to the cold plate, and the monitoring device is communicatively connected to the pressure detection member and is used to determine whether the battery pack is delaminated according to the detection result obtained by the pressure detection member.

[0014] In a second aspect, the present application provides a method for manufacturing a battery pack, which is applied to the battery pack described in any of the above embodiments. The manufacturing method includes: During the process of pressing the battery cell group into the box body by using a pressing mechanism, detecting the downward pressure exerted by the pressing mechanism on the cold plate through the battery cell group; According to the downward pressure, controlling a power pump connected to the filling member to inject the fluid into the cavity until the supporting force provided by the fluid in the cavity of the flexible member to the cold plate is equivalent to the downward pressure.

[0015] In a third aspect, the present application provides a method for detecting delamination of a battery pack, which is applied to the battery pack described in any of the above embodiments. The delamination detection method includes: Monitoring the fluctuation of the supporting force provided by the fluid in the cavity of the flexible member to the cold plate; When the fluctuation of the supporting force exceeds the allowable fluctuation range, determining that the battery pack is delaminated; Outputting a delamination prompt message.

[0016] Compared with the prior art, the present application has the following beneficial effects: In the above battery pack, its manufacturing method, and delamination detection method, during the battery pack assembly process, after placing the flexible member and the cold plate inside the box body, applying a thermal conductive adhesive on the upper surface of the cold plate. During the process of loading the battery cell group into the box body, using a pressing mechanism to apply a downward pressure on the battery cell group, and this downward pressure is transmitted to the cold plate. At this time, the fluid supply device can adjust the fluid content in the cavity through the filling member, so that the supporting force provided by the flexible member to the cold plate is basically equivalent to the downward pressure received by the cold plate, enabling the cold plate to be evenly stressed up and down, avoiding local depression of the cold plate, ensuring that the thermal conductive structural adhesive filled between the cold plate and the battery cell group can be evenly distributed and have a basically consistent thickness during the downward pressing process of the battery cell group, enabling the cold plate to exchange heat evenly with the battery cell group, and further improving the thermal management effect of the battery pack.

[0017] In addition, it is also possible to determine whether the battery pack is delaminated according to the fluctuation of the supporting force provided by the fluid in the flexible member to the cold plate, which can timely detect abnormal conditions of the battery pack and improve the use reliability of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. Moreover, in all the drawings, the same reference numerals are used to represent the same components. In the drawings: Figure 1 It is a schematic external view of a battery pack for some embodiments.

[0019] Figure 2 is Figure 1 exploded view of the battery pack shown in the figure.

[0020] Figure 3 is Figure 1 partial internal structure diagram of the battery pack shown in the figure.

[0021] Figure 4 is the connection diagram of the flexible part and the pipeline in some embodiments.

[0022] Figure 5 is Figure 4 perspective view of the structure shown in the figure.

[0023] Figure 6 is Figure 1 another azimuth view of the battery pack shown in the figure.

[0024] Figure 7 is Figure 6 enlarged view of the position A in

[0025] Figure 8 is the structure diagram of the filling part in some embodiments.

[0026] Figure 9 is the assembly process diagram of the battery pack in some embodiments.

[0027] Figure 10 is the process flow diagram of the preparation method of the battery pack in some embodiments.

[0028] Figure 11 is the process flow diagram of the degumming detection method of the battery pack in some embodiments.

[0029] The reference numerals in the specific embodiments are as follows: 100, battery pack; 10, box body; 11, bottom guard plate; 11a, accommodation groove; 12, filling part; 12a, core body; a1, core cavity; a11, first cavity section; a12, second cavity section; 12b, thimble; b1, shoulder; 12c, sealing plug; 12d, elastic part; 12e, valve body; e1, through hole; 20, battery cell group; 30, thermal conductive structural adhesive; 40, cold plate; 40a, avoidance part; 41, upper plate; 42, lower plate; 50, flexible part; k, cavity; 51, support frame; 52, elastic bladder; 53, partition part; 53a, partition groove; 54, thinning part; 60, end plate; G, pipeline; 200, downward pressing mechanism; 300, clamping mechanism. Specific embodiments

[0030] To make the above objects, features, and advantages of the present application more apparent and understandable, the following provides a detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings. Many specific details are set forth in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0031] In the description of the present application, it should be understood that if present, the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0032] In addition, if present, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0033] In the present application, unless otherwise clearly specified and limited, if present, the terms "install", "connect", "couple", "fix", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0034] In this application, if it appears, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the horizontal height of the first feature is less than that of the second feature.

[0035] It should be noted that if it appears, when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only implementation.

[0036] In view of the technical problem pointed out in the background art that during the process of assembling a battery pack, when pressing on the battery cell group, the cold plate located at the bottom of the battery pack is squeezed by the battery cell group, and local depression is likely to occur, resulting in uneven thickness of the thermal conductive structural adhesive filled between the cold plate and the battery cell group, affecting the thermal management effect of the battery pack, this application proposes a battery pack.

[0037] The battery pack involved in the embodiment of this application is internally provided with at least one group of battery cell groups. Each battery cell group includes a plurality of battery cells arranged side by side. A battery cell is the smallest unit for electrochemical reaction in a battery and can be a secondary battery or a primary battery. The battery cell can be a lithium-ion battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto. The battery cell can be in the shape of a cylinder, a flat body, a cuboid or other shapes, etc.

[0038] In one embodiment, the battery cell includes a housing, an end cap and an electrode assembly. The housing and the end cap together form an internal space for accommodating the electrode assembly. Specifically, an accommodation cavity is formed in the housing and at least one end is open, and the end cap covers the open end of the housing to close the accommodation cavity, and the electrode assembly is loaded in the accommodation cavity. The housing can be but is not limited to a metal housing, such as an aluminum shell, a steel shell, etc.

[0039] The electrode assembly generally includes a positive electrode sheet, a negative electrode sheet and a separator for separating the positive electrode sheet and the negative electrode sheet. An electrolyte can be injected into the battery cell, and the electrolyte infiltrates the inside of the electrode assembly, providing an ion migration path for the electrode assembly to carry out electrochemical reactions and playing a role in conduction. The electrode assembly can be in the form of a wound type, a stacked type, etc. One or more electrode assemblies can be loaded in the battery cell.

[0040] The battery pack in the embodiment of the present application will be described in detail below.

[0041] Please refer to Figure 1 、 Figure 2 and Figure 3 , the battery pack 100 in the embodiment of the present application includes a box body 10, a battery cell group 20, a thermal conductive structural adhesive 30, and a cold plate 40 stacked in sequence along the Z direction, as well as a flexible member 50 and a filling member 12. The box body 10 includes a bottom protection plate 11, and the Z direction is the thickness direction of the bottom protection plate 11. The flexible member 50 is disposed on the bottom protection plate 11 and supports on the side of the cold plate 40 facing away from the thermal conductive structural adhesive 30. Along the Z direction, the projection of the flexible member 50 overlaps with the projection of the battery cell group 20. The flexible member 50 has a cavity k inside, and a fluid is loaded in the cavity k. The flexible member 50 is configured to expand and contract with the change of the fluid content in the cavity k to adjust the supporting force of the flexible member 50 acting on the cold plate 40. The filling member 12 is communicated with the cavity k and can allow the fluid to enter and exit the cavity k to control the fluid content in the flexible member 50.

[0042] The bottom protection plate 11 can be used as the bottom plate of the box body 10 to close the bottom of the box body 10. The bottom protection plate 11 can be a flat plate structure, or its bottom can protrude outward to form a concave plate structure with an inward concave. In a use state, the thickness direction of the bottom protection plate 11 corresponds to the vertical direction. The flexible member 50, the cold plate 40, the thermal conductive structural adhesive 30, and the battery cell group 20 are sequentially arranged from bottom to top and supported on the bottom protection plate 11. In an embodiment, the box body 10 further includes side plates and a cover plate. The side plates are arranged around the outer periphery of the bottom protection plate 11, and the two enclose a receiving space with one end open. The cold plate 40, the battery cell group 20, and the flexible member 50 are loaded into the receiving space through the open end, and the cover plate covers the open end of the receiving space.

[0043] The cold plate 40 is in a plate shape, and a flow channel for circulating a heat exchange medium is arranged inside it. The heat exchange medium exchanges heat with the battery cell group 20 through the cold plate 40 and the thermal conductive structural adhesive 30 in sequence to adjust the temperature of the battery cell group 20. The thermal conductive structural adhesive 30 fills between the cold plate 40 and the battery cell group 20, enabling uniform heat exchange between the two.

[0044] On the upper side of the cold plate 40, multiple groups of battery cell groups 20 are usually arranged. In each battery cell group 20, the battery cells are arranged in the same direction side by side, and each group of battery cell groups 20 is thermally connected to the cold plate 40 through a thermally conductive structural adhesive 30. The flexible member 50 is supported at the bottom of the cold plate 40 to provide a supporting force to the cold plate 40. In the Z direction, the projection of the flexible member 50 overlaps with the projection of the battery cell group 20, and the portion of the cold plate 40 pressed down by the battery cell group 20 can be effectively supported by the flexible member 50, preventing the cold plate 40 from being dented by the battery cell group 20. Optionally, one or more flexible members 50 are arranged below each battery cell group 20. Optionally, the same flexible member 50 is correspondingly arranged below all the battery cell groups 20. Regardless of the arrangement of the battery cell group 20 and the flexible member 50, preferably, the projection of the battery cell group 20 in the Z direction is located within the projection range of the flexible member 50, which can effectively ensure uniform force on the cold plate 40.

[0045] The flexible member 50 is a hollow structure, and its interior is provided with a cavity k. A fluid is loaded in the cavity k. The fluid can be a gas (such as nitrogen, carbon dioxide, air, etc.), a liquid (such as water), or a mixture thereof. Optionally, the fluid is selected as a liquid, which is almost incompressible and can provide a more stable and reliable support. The flexible member 50 is made of a flexible material, and it can expand and contract with the change of the fluid content in the cavity k. Specifically, the flexible member 50 can be selected from rubber, thermoplastic polyurethane (TPU), ethylene-tetrafluoroethylene copolymer (ETFE), polyethylene (PE), polypropylene (PP), aluminum plastic film, ethylene propylene diene terpolymer (EPDM), etc. When the fluid content in the cavity k is relatively large, the flexible member 50 is expanded outward by the fluid and can provide a relatively large supporting force to the cold plate 40. When the fluid content in the cavity k is relatively small, the flexible member 50 can elastically retract, reducing the supporting force on the cold plate 40.

[0046] The filling member 12 can be arranged outside and / or inside the box body 10. The flexible member 50 is provided with an interface corresponding to the cavity k. The filling member 12 is communicated with the interface of the flexible member 50 through a pipeline G. An external fluid supply device injects fluid into the cavity k through the filling member 12 and / or the fluid in the cavity k can flow back to the fluid supply device through the filling member 12. In actual application, the fluid supply device can change the fluid content in the cavity k through the filling member 12, thereby changing the magnitude of the supporting force provided by the flexible member 50.

[0047] During the assembly process of the battery pack 100, after placing the flexible member 50 and the cold plate 40 inside the box body 10, thermal conductive adhesive is coated on the upper surface of the cold plate 40. During the process of loading the battery cell group 20 into the box body 10, a downward pressure is applied to the battery cell group 20 by the downward pressing mechanism 200, and this downward pressure is transmitted to the cold plate 40. At this time, the fluid supply device can adjust the fluid content in the cavity k through the filling member 12, so that the supporting force provided by the flexible member 50 to the cold plate 40 is basically equivalent to the downward pressure received by the cold plate 40, and the cold plate 40 can be evenly stressed up and down, avoiding local depression of the cold plate 40. The thermal conductive structural adhesive 30 filled between the cold plate 40 and the battery cell group 20 can be evenly distributed and have a basically consistent thickness during the downward pressing process of the battery cell group 20, enabling the cold plate 40 to exchange heat evenly with the battery cell group 20, thereby improving the thermal management effect of the battery pack 100.

[0048] Understandably, the setting of the filling member 12 can supply the fluid supply device to fill the cavity k of the flexible member 50 with fluid during the assembly process of the battery pack 100. After the battery pack 100 is assembled, the filling member 12 is not connected to the fluid supply device and the filling member 12 is closed to avoid fluid leakage in the battery pack 100.

[0049] In some embodiments, multiple flexible members 50 and battery cell groups 20 are configured. In the Z direction, a flexible member 50 is arranged corresponding to each battery cell group 20 one by one. Since there may be a certain arrangement gap between the battery cell groups 20, at this time, a flexible member 50 is arranged corresponding to the lower part of each battery cell group 20, which can not only reduce the number of flexible members 50, simplify the production arrangement, but also reduce the overall use area of the flexible members 50 and lower the cost.

[0050] It is worth mentioning that in actual application, the arrangement position of the flexible member 50 relative to the battery cell group 20 can be designed according to the pressure action position of the downward pressing mechanism 200 on the battery cell group 20. Specifically, the flexible member 50 is at least arranged below the pressure action position of the corresponding battery cell group 20. In this way, it is not necessary for the projection of the battery cell group 20 to completely fall within the projection range of the flexible member 50. The flexible member 50 can not only effectively provide a supporting force, but also reduce the use area of the flexible member 50 and lower the cost.

[0051] In some embodiments, multiple filling members 12 are configured, and the cavities k of each flexible member 50 are independently connected to a filling member 12 via a pipeline G. In this way, through each filling member 12, fluids can be filled into each flexible member 50 synchronously or each flexible member 50 can discharge fluids synchronously, accelerating the overall fluid filling / discharging speed of the battery pack 100, enabling the flexible members 50 as a whole to reach the required supporting force faster, and enabling the cold plate 40 to reach the state of balanced stress up and down faster, reducing the probability of its depression. Moreover, each filling member 12 integrates two functions of fluid entering and leaving the cavity k, which can reduce the number of filling members 12 and lower the cost.

[0052] In other embodiments, multiple flexible members 50 may also share one filling member 12, or multiple filling members 12 communicate with the cavity k of one flexible member 50 through a pipeline G. When each cavity k is correspondingly connected to multiple filling members 12, some of the filling members 12 may be used for fluid to flow into the cavity k, and the remaining filling members 12 may be used for fluid to flow out of the cavity k.

[0053] In some embodiments, with reference to Figure 4 , the flexible member 50 is in one-to-one correspondence and communication with the filling member 12, and the same flexible member 50 communicates with its own cavity k and the corresponding filling member 12 through multiple pipelines G.

[0054] The positions on the flexible member 50 connected to the pipelines G are defined as interfaces, and multiple interfaces are provided on the flexible member 50 and are correspondingly connected to each pipeline G. At this time, the fluid can enter and exit the flexible member 50 through the multiple interfaces on each flexible member 50, improving the filling rate and discharge rate of the fluid in each flexible member 50, and the flexible member 50 can provide the required supporting force faster.

[0055] The number of cavities k in each flexible member 50 can be one or more. When the number of cavities k is one, the fluid can enter and exit multiple positions of the cavity k synchronously through each interface, accelerating the fluid's entry and exit from the cavity k. When the number of cavities k is multiple, at least one interface is correspondingly provided for each cavity k, and the fluid enters and exits each cavity k through each interface, and the fluid in each cavity k can enter and exit synchronously, and the flexible member 50 can also quickly provide the required supporting force. It can be understood that each cavity k can be correspondingly connected to at least one interface, and when there are multiple cavities k, the number of interfaces connected to each cavity k is the same, which is beneficial to keeping the entry and exit rates of the fluid in each cavity k basically consistent.

[0056] In other embodiments, if the flexible member 50 includes multiple cavities k and the cavities k communicate with each other, interfaces can be provided on the flexible member 50 corresponding to one or some of the cavities k, and fluid can also enter and exit each cavity k.

[0057] In some embodiments, in combination with Figure 4 it is understood that the flexible member 50 includes an elastically expandable support frame 51, and the cold plate 40 is supported on the support frame 51. The cavity k is located inside the support frame 51, and the support frame 51 has an initial volume. When the volume of the cavity k caused by the fluid exceeds this initial volume, the support frame 51 is extruded and expanded by the fluid, increasing its volume.

[0058] The support frame 51 forms the outer shape of the flexible member 50. Specifically, the interior of the support frame 51 is hollow and has an initial volume, which can elastically expand based on the initial volume and basically return to the initial volume after the expansion disappears. Before the battery cell group 20 is loaded into the box body 10, when the cold plate 40 is supported on the support frame 51, the support frame 51 basically maintains its initial volume under the gravity of the cold plate 40, that is, the stiffness of the support frame 51 supports its support for the cold plate 40. In addition, when the support frame 51 is in the initial volume, it maintains a slightly outwardly expanded state, so as to compensate for the assembly gap between the support frame 51 and the cold plate 40 when supporting the cold plate 40, and play a flexible support role for the cold plate 40, thereby not only avoiding the depression of the cold plate 40 during assembly, but also buffering the cold plate 40 during the use of the battery pack to avoid deformation of the cold plate 40 caused by vibration and impact.

[0059] The cavity k is located within the support frame 51. Specifically, the internal space of the support frame 51 can be directly used as the cavity k, and the cavity k has a minimum volume, that is, this initial volume. When the fluid content in the cavity k exceeds the size of the initial volume, the fluid squeezes the support frame 51 and causes the support frame 51 to expand, and both the volume of the support frame 51 and the volume of the cavity k increase. When the fluid content in the cavity k does not exceed the size of the initial volume, the fluid cannot squeeze the support frame 51, and the support frame 51 basically remains at the initial volume.

[0060] When the support frame 51 remains at the initial volume, the outer shape of the flexible member 50 can be shaped and will not collapse. Thus, before the battery cell group 20 is loaded and no fluid is filled or the fluid filling amount is insufficient (the fluid does not squeeze the support frame 51), the cold plate 40 can be stably placed on the flexible member 50 to effectively support the cold plate 40, ensuring that the cold plate 40 will not tilt or be unstable, and further contributing to the uniform distribution of the thickness of the thermal conductive structural adhesive 30 coated on the cold plate 40.

[0061] In order to enable the support frame 51 to be flexibly expandable and basically maintain the initial volume when not squeezed by the fluid, one implementation means is that the support frame 51 is made of a flexible material with relatively high rigidity, such as fiber-reinforced rubber or TPU. At this time, the support frame 51 may undergo a certain deformation under the gravity of the cold plate 40, but its internal volume basically remains at the initial volume and can effectively support the cold plate 40. Another implementation means is that the side and / or bottom surface of the support frame 51 is provided with a structure (such as a reinforcing rib) or a coating (such as a metal coating, a ceramic coating) for enhancing the stiffness or is directly made of a rigid material, as long as it is ensured that the top surface of the support frame 51 for supporting the cold plate 40 is easily expandable and deformable. Further, the above-mentioned structures and coatings for enhancing the stiffness can also be provided on the top surface of the support frame 51 to further enhance its stiffness while ensuring that it has a certain flexibility and can expand and deform.

[0062] In some embodiments, in combination with Figure 5It is understood that the flexible member 50 further includes an elastic bladder 52 that forms a cavity k. The elastic bladder 52 is located within the support frame 51, and the volume of the elastic bladder 52 can change with the content of the internal fluid. When the fluid causes the volume of the elastic bladder 52 to exceed the initial volume, the support frame 51 is squeezed by the elastic bladder 52 and expands to increase its volume.

[0063] The elastic bladder 52 can be understood as an airbag structure that can expand and contract with the increase or decrease of the fluid content. When the fluid content in it does not cause its volume to exceed the initial volume, the elastic bladder 52 cannot squeeze the support frame 51, and the cold plate 40 is mainly supported by the support frame 51. When the fluid content in the elastic bladder 52 is relatively large and causes its volume to exceed the initial volume, the elastic bladder 52 expands and squeezes the support frame 51. The support frame 51 can elastically expand and deform under the extrusion of the elastic bladder 52, thereby increasing the support force on the cold plate 40. That is to say, the support frame 51 expands and deforms (the volume of the accommodation cavity increases) following the elastic bladder 52 when the volume of the elastic bladder 52 exceeds the initial volume of its accommodation cavity. When the extrusion effect of the elastic bladder 52 disappears, the support frame 51 basically returns to the initial volume.

[0064] It can be understood that the rigidity of the elastic member 12d is less than that of the support frame 51. It can be made of a flexible material with relatively low rigidity, such as aluminum plastic film, silicone rubber, EPDM, etc., and it is easily deformed under the action of the fluid.

[0065] At this time, the elastic bladder 52 forms a cavity k within the support frame 51. On the one hand, the setting of the elastic bladder 52 is conducive to forming multiple independent cavities k within the support frame 51, and has good fluid tightness, which can effectively prevent fluid outflow and cause electrical safety. On the other hand, since the elastic bladder 52 can expand and contract with the increase or decrease of the fluid content, it can more accurately monitor the pressure generated by the fluid in the cavity k, making the fluid pressure within the flexible member 50 precisely controllable. Furthermore, it is beneficial to more accurately determine the support force provided by the flexible member 50, making the forces on the upper and lower sides of the cold plate 40 uniform. In addition, multiple independent cavities k can more accurately monitor the pressures at different positions of the cold plate 40, which is further beneficial to improving the force uniformity at different positions of the cold plate 40.

[0066] In other embodiments, the flexible member 50 itself can also be formed only by the above-mentioned elastic bladder 52. In order to enable the flexible member 50 to maintain a certain shape to effectively support the cold plate 40, a certain content of fluid can be pre-stored in the elastic bladder 52, and at least this content of fluid should be retained in the elastic bladder 52 during the process of fluid entering and leaving the cavity k.

[0067] In the above embodiments, a support frame 51 is added outside the elastic bladder 52. In addition to the above beneficial effects, since the support frame 51 plays a role of qualitative restraint, there is no need to reserve fluid in the elastic bladder 52. Thus, the weight of the flexible member 50 can be reduced during the assembly stage, and the assembly is more labor-saving. Moreover, the step of filling fluid can be omitted during the production stage. While ensuring that the fluid pressure of the flexible member 50 is accurately controllable, the production of the flexible member 50 can be simplified.

[0068] Preferably, the support frame 51 has insulation properties and can play an insulating role between the cold plate 40 and the bottom guard plate 11, reducing the risk of the bottom guard plate 11 being electrified when the battery cell group 20 leaks electricity. When the elastic bladder 52 is made of a conductive material such as an aluminum-plastic film, the support frame 51 can also play the role of insulating the elastic bladder 52.

[0069] In some embodiments, as Figure 5 shown, a plurality of elastic bladders 52 are arranged in the support frame 51, and all the elastic bladders 52 are sequentially separated and arranged in the X direction, where the X direction is the length direction of the bottom guard plate 11. Each elastic bladder 52 in the same support frame 51 is independently connected to the filling member 12 via a pipeline G.

[0070] In actual application, the battery cells in the battery cell group 20 can be arranged side by side along the length direction of the bottom guard plate 11, or can be arranged side by side along the width direction of the bottom guard plate 11.

[0071] The support frame 51 extends longitudinally in the X direction, and a plurality of elastic bladders 52 are sequentially arranged inside it along the X direction. Each elastic bladder 52 can be arranged corresponding to different pressure acting positions of the same battery cell group 20 or different pressure acting positions of different battery cell groups 20. The arrangement of the plurality of elastic bladders 52 enables each flexible member 50 to provide a supporting force for each pressure acting position in a partitioned manner, with a better supporting effect and more uniform force on the cold plate 40.

[0072] The supporting forces provided by the respective elastic bladders 52 can be the same or different. In some embodiments, at least some of the elastic bladders 52 provide unequal supporting forces. For example, for the middle region of the battery cell group 20 or the region where the battery cell group 20 in the middle is located, elastic bladders 52 with a greater supporting force can be provided. Designing elastic bladders 52 with different supporting forces can be done through conventional designs in terms of the filling content of the fluid in the elastic bladder 52, the material of the elastic bladder 52, the shape and size of the elastic bladder 52, etc., and will not be specifically elaborated here.

[0073] It is worth mentioning that when the battery cell group 20 is assembled, in order to improve the pressure application uniformity, pressure is applied to the middle area of the battery cell group 20 or the battery cell group 20 located in the middle, so that the depression phenomenon existing in the cold plate 40 area corresponding to the middle area of the battery cell group 20 or the battery cell group 20 located in the middle is more serious. At this time, an elastic bladder 52 with a greater supporting force can be designed to increase the supporting force here, improve the force uniformity of the cold plate 40, improve the consistency of the thickness of the heat-conducting structural adhesive, and thus improve the heat exchange effect. In addition, when the periphery of the cold plate 40 is fixed to the box body 10, when the middle area of the cold plate 40 is pressed, greater stress concentration will be generated due to boundary constraints, and the middle area is more likely to cause depression. At this time, an elastic bladder 52 with a greater supporting force is arranged corresponding to the middle area of the cold plate 40, which can increase the supporting force here and further improve the force uniformity of the cold plate 40.

[0074] It should be noted that the middle area of the cold plate 40 is called the first area, and the area of the cold plate 40 corresponding to the middle area of the battery cell group 20 or the battery cell group 20 located in the middle is called the second area. The first area and the second area can be different, and the set supporting forces can be different. At this time, the supporting forces of the two areas can be set as needed to reduce the uneven force caused by different deformations; in another embodiment, the first area and the second area can also be the same. At this time, under the dual action, the depression phenomenon existing in the cold plate 40 is particularly serious, and the supporting force here can be further increased to avoid the depression phenomenon of the cold plate 40 and ensure the force uniformity of the cold plate 40.

[0075] In a specific embodiment, each elastic bladder 52 in the same support frame 51 is independently communicated with a filling member 12 via a pipeline G. Specifically, each elastic bladder 52 can be communicated with different filling members 12 or the same filling member 12. Optionally, each elastic bladder 52 in the same support frame 51 is connected in parallel to the same filling member 12. In this way, the number of filling members 12 can be reduced, and at the same time, each elastic bladder 52 can be filled with fluid synchronously, and the fluid filling efficiency is relatively high. The partitions where each elastic bladder 52 is located can basically provide supporting forces to each pressure action position synchronously, avoiding the depression of the cold plate 40 due to untimely local support.

[0076] It is worth mentioning that when each elastic bladder 52 of the same support frame 51 is connected in parallel to the same filling member 12, the fluid content flowing into the elastic bladder 52 within the same time can be controlled by designing the inner diameter of the pipeline G connected to the elastic bladder 52, so as to control the supporting force provided by the elastic bladder 52, so that the supporting forces provided by at least some elastic bladders 52 are different. The supporting force is equal to the product of the pressure and the contact area. Optionally, when filling the same content of fluid, the pressure of the elastic bladder 52 can be made different by designing the size of the elastic bladder 52, and the size of the area where it provides the supporting effect can be reasonably designed to make the supporting force provided by the elastic bladder 52 different.

[0077] In some embodiments, the support frame 51 includes a partition portion 53 that separates adjacent elastic capsules 52. On the one hand, the arrangement of the partition portion 53 can form multiple placement areas in the support frame 51, and each elastic capsule 52 is placed in a corresponding placement area one by one, accelerating the rapid partitioned placement of the elastic capsules 52. Moreover, the partition portion 53 separates each elastic capsule 52 to prevent adjacent elastic capsules 52 from squeezing each other during expansion, facilitating the accurate acquisition of the pressure generated by the fluid in each elastic capsule 52 and being conducive to precisely controlling the fluid filling amount of the elastic capsules 52.

[0078] Among them, the partition portion 53 may include partition plates, partition ribs, etc. provided in the support frame 51.

[0079] In some embodiments, referring to Figure 5 , the partition portion 53 includes a partition groove 53a recessed in the outer surface of the support frame 51. The partition groove 53a extends along the Y direction intersecting the X direction, and the Y direction is the width direction of the bottom protection plate 11. On the one hand, the partition groove 53a can serve as a reinforcing rib to increase the stiffness of the support frame 51. Moreover, by using the partition groove 53a recessed in the outer surface of the support frame 51 as the partition portion 53, it will not increase the space occupied by the support frame 51, is also conducive to the layout of the support frame 51, and simplifies the processing of the support frame 51.

[0080] In some embodiments, the battery cell group 20 includes an explosion-proof valve. The explosion-proof valve is located on one side of the battery cell group 20 facing the cold plate 40 along the Z direction, and the thermally conductive structural adhesive 30 avoids the explosion-proof valve. The cold plate 40 is provided with an avoidance portion 40a, and the flexible member 50 is provided with a thinning portion 54. The explosion-proof valve, the avoidance portion 40a, and the thinning portion 54 are arranged corresponding to each other along the Z direction. The avoidance portion 40a and the thinning portion 54 are configured to be able to allow the high-temperature and high-pressure flue gas released when the explosion-proof valve relieves pressure to flow through. The fluid filled in the cavity k includes a fire extinguishing substance, and the thinning portion 54 allows the high-temperature and high-pressure flue gas to enter the cavity k to be cooled by the fire extinguishing substance.

[0081] Specifically, a plurality of explosion-proof valves are provided at the bottom of each battery cell group 20, and the plurality of explosion-proof valves are arranged side by side along the length direction or the width direction of the bottom protection plate 11. The cold plate 40 is provided with avoidance portions 40a corresponding to each explosion-proof valve, and the flexible member 50 is provided with thinning portions 54 corresponding to each avoidance portion 40a.

[0082] In one embodiment, the cold plate 40 is an integral piece for heat exchange with all the battery cell groups 20, and the avoidance portion 40a is an avoidance hole provided on the cold plate 40. In another embodiment, the cold plate 40 is composed of multiple pieces, and the gap between adjacent cold plates 40 serves as the avoidance gap for the avoidance portion 40a.

[0083] The thinning portion 54 can be a scored structure obtained by locally thinning the flexible member 50, and the scored structure can be in the shape of a cross, a single line, a circle, an annular shape, a wavy shape, etc. The thinning portion 54 can also be obtained by processing a hole structure in the flexible member 50 and then arranging a thin film structure with a smaller thickness at the hole structure, and the thin film structure functions as a seal.

[0084] The fire extinguishing substance in the cavity k can include hot aerosol, heptafluoropropane gas, hexafluoropropane, carbon dioxide, foam fire extinguishing agent, perfluorohexanone liquid, etc.

[0085] In actual application, when the explosion-proof valve relieves pressure, the high-temperature and high-pressure flue gas is sprayed towards the cold plate 40, breaks through the thinning portion 54 after passing through the avoidance portion 40a, and releases the fire extinguishing substance in the cavity k, playing a role in active fire extinguishing and temperature reduction, preventing heat spread, and improving the safety of the battery pack 100.

[0086] Specifically, if the flexible member 50 includes the above-mentioned support frame 51, the thinning portion 54 is arranged on the support frame 51. If the flexible member 50 only includes the above-mentioned support frame 51, the fire extinguishing substance is directly filled in the cavity k formed by the support frame 51. When the thinning portion 54 is broken through, the fire extinguishing substance in the cavity k is released for active fire extinguishing and temperature reduction. If the flexible member 50 further includes an elastic bladder 52 located within the support frame 51, the elastic bladder 52 forms the cavity k. When the thinning portion 54 is broken through, the high-temperature and high-pressure flue gas acts on the elastic bladder 52, causing the elastic bladder 52 to melt / break and release the fire extinguishing substance. For example, a structure such as the above-mentioned score is arranged on the elastic bladder 52. After the high-temperature and high-pressure flue gas enters the support frame 51, it breaks through the score on the elastic bladder 52 to make its structure damaged and release the fire extinguishing substance. The elastic bladder 52 can also be made of a flexible polymer material with a lower melting point, such as PP, PE, TPU, etc. After the high-temperature and high-pressure flue gas enters the support frame 51, it melts the elastic bladder 52 to release the fire extinguishing substance.

[0087] In some embodiments, in combination Figure 2 and Figure 6 Understand that a receiving groove 11a is formed by the side of the bottom guard plate 11 facing the cold plate 40 being recessed away from the cold plate 40, and the flexible member 50 and the pipeline G communicating with the flexible member 50 are arranged in the receiving groove 11a. In this way, on the basis of the existing battery pack 100, only the structure of the bottom guard plate 11 needs to be improved to realize the accommodation of the flexible member 50 and its pipeline G, which can simplify the preparation of the battery pack 100 and reduce the improvement cost of the battery pack 100.

[0088] Specifically in the embodiment, as Figure 6 shown, the filling member 12 is arranged on the lateral peripheral wall of the bottom guard plate 11. Optionally, a plurality of filling members 12 are arranged on the lateral peripheral wall of the bottom guard plate 11. In this way, it is convenient for the pipeline G to route.

[0089] In some embodiments, with reference toFigure 8 , the filling member 12 includes a valve body 12e, a core body 12a, a thimble 12b, and a sealing plug 12c. The valve body 12e has a through hole e1, and the core body 12a, the thimble 12b, and the sealing plug 12c are all arranged in the through hole e1. A core cavity a1 is provided in the core body 12a, the thimble 12b passes through the core cavity a1, and is movably arranged relative to the core body 12a in the depth direction of the through hole e1. The sealing plug 12c is fixed to the thimble 12b and can open and close the core cavity a1 when moving with the thimble 12b.

[0090] Specifically, mounting holes are provided on the bottom guard plate 11, and the valve body 12e is installed at the mounting holes, serving to house the core body 12a, the thimble 12b, and the sealing plug 12c. The valve body 12e and the bottom guard plate 11 can be fixed by means such as gluing, laser welding, and cold pressing. The core body 12a is fixed in the through hole e1, the thimble 12b passes through the core cavity a1 of the core body 12a, and both ends extend out of the core cavity a1. One end is used to cooperate with an external interface, and the other end is connected to the sealing plug 12c.

[0091] In actual application, combined with Figure 8 description, after the interface of the fluid supply device is docked with the left end of the valve body 12e, the interface pushes the thimble 12b to move rightward along the core cavity a1, so that the pipeline G connected to the right end of the valve body 12e is communicated with the fluid supply device, and the fluid can enter and exit the cavity k of the flexible member 50 through the through hole e1. When the interface of the fluid supply device withdraws from the left end of the valve body 12e, the ejector rod moves leftward and drives the sealing plug 12c to close the core cavity a1.

[0092] At this time, by using the valve body 12e to house the ejector rod, the core body 12a, and the sealing plug 12c, it is possible to prevent the filling member 12 from being accidentally touched and conducted by external forces, and improve the reliability of use of the filling member 12. Moreover, by using the ejector rod to drive the sealing plug 12c to open and close the core cavity a1 to achieve the conduction and cutting-off of the filling member 12, the structure is simple and easy to implement.

[0093] In some embodiments, the filling member 12 further includes an elastic member 12d. The elastic member 12d is connected to the thimble 12b and is used to provide an elastic force for the thimble 12b to drive the sealing plug 12c to close the core cavity a1. In this way, when the external interface withdraws, under the action of the elastic member 12d, the thimble 12b can automatically return to the position where the sealing plug 12c closes the core cavity a1, and the filling member 12 will not leak liquid, and the use is more reliable.

[0094] Regarding the setting of the elastic member 12d, in one embodiment, the elastic member 12d includes a spring plate arranged in the through hole e1. One end of the spring plate is connected to the hole wall of the through hole e1, and the other end is connected to the thimble 12b. When the thimble 12b is squeezed by the external interface and moves rightward, the spring plate is stretched. When the external interface withdraws, the spring plate resets and pulls the thimble 12b back to its original position. In another embodiment, referring to Figure 8, the core cavity a1 includes a first cavity section a11 and a second cavity section a12 that are coaxially connected along the depth direction of the through hole e1. The inner diameter of the first cavity section a11 is larger than that of the second cavity section a12. The first cavity section a11 is arranged on the side of the second cavity section a12 away from the sealing plug 12c. The elastic member 12d includes a spring arranged in the first cavity section a11. The spring is sleeved on the thimble 12b. The thimble 12b includes a shoulder b1 located in the first cavity section a11. The first cavity section a11 has an inner wall that is spaced apart from the shoulder b1 in the depth direction of the through hole e1. The spring is limited in the space between the inner wall and the shoulder b1. When the thimble 12b is pushed by an external interface and moves to the right end, the spring is compressed. When the external interface is removed, the spring resets and pushes the thimble 12b back to its original position.

[0095] In other embodiments, the elastic member 12d may not be provided, and the position restoration of the thimble 12b can be achieved by the driving of the external interface. In other embodiments, a spring may also be arranged on one side of the sealing plug 12c. The spring resets to push the sealing plug 12c to close the core cavity a1 and push the ejector rod back to its position.

[0096] In some embodiments, the battery pack 100 further includes a monitoring device and a pressure detection member. The pressure detection member is used to determine the supporting force provided by the fluid in the cavity k to the cold plate 40. The monitoring device is communicatively connected to the pressure detection member and is used to determine whether the battery pack 100 is delaminated according to the detection result obtained by the pressure detection member.

[0097] The pressure detection member can be a piezoelectric sensor, a piezoresistive sensor, etc. Specifically, the pressure detection member can be arranged at one end of the filling member 12 communicating with the cavity k, or in the pipeline G communicating with the cavity k, or in the cavity k, or between the flexible member 50 and the cold plate 40. It is worth mentioning that the pressure P (unit: Mpa) detected by the pressure detection member refers to the force received per unit area. The supporting force F provided by the flexible member 50 to the cold plate 40 can be determined by P*S, where S is the contact area between the flexible member 50 and the cold plate 40 and can be set as a default value.

[0098] The monitoring device can be a battery management system (BMS) or other processing devices arranged in the battery pack 100. The delamination of the battery pack 100 means that the thermal conductive adhesive 30 between the cold plate 40 and the battery cell group 20 is detached (locally detached). When the battery pack 100 is subjected to external impacts and other dangers, the thermal conductive adhesive 30 is likely to be detached, reducing the heat transfer efficiency and effect between the cold plate 40 and the battery cell group 20. When the thermal conductive adhesive 30 is detached, the pressure detected by the pressure detection member will fluctuate. After the monitoring device detects this fluctuation, it determines that the battery pack 100 is delaminated.

[0099] In this way, the flexible member 50 can not only effectively support the cold plate 40, making the upper and lower forces balanced, but also be used to detect whether the thermally conductive structural adhesive 30 is delaminated, so as to timely discover the abnormal conditions of the battery pack 100, serving multiple purposes with one object.

[0100] Please refer to Figure 9 and Figure 10 , the embodiment of the present application further provides a preparation method of the battery pack 100. Applying the battery pack 100 of any of the above embodiments, the preparation method includes: S1. During the process of pressing the battery cell group 20 into the box body 10 by the pressing mechanism 200, monitor the downward pressure exerted by the pressing mechanism 200 on the cold plate 40 through the battery cell group 20. Specifically, clamp the end plates 60 at both ends of the battery cell group 20 by the clamping mechanism to send it into the box body 10, and use the pressing mechanism 200 to press on the battery cell group 20 to press the battery cell group 20 into the box body 10. In order to detect the downward pressure exerted by the pressing mechanism 200 on the cold plate 40, it can be but is not limited to setting a pressure sensor at the pressure action position where the pressing mechanism 200 acts on the battery cell group 20 to determine the downward pressure of the cold plate 40. When there are multiple pressure action positions of the pressing mechanism 200 on the battery cell group 20, the downward pressure is determined according to the sum of the pressures at each pressure action position. A pressure sensing structure can also be set at the pressing head of the pressing mechanism 200 to monitor the downward pressure provided by the pressing mechanism 200.

[0101] S2. According to this downward pressure, control the power pump connected to the filling member 12 to inject fluid into the cavity k until the supporting force provided by the fluid in the cavity k of the flexible member 50 to the cold plate 40 is equivalent to the downward pressure.

[0102] The fluid providing device is connected to the filling member 12 via a power pump. A pressure sensor can be set at the power pump to obtain the real-time fluid pressure. Of course, the real-time fluid pressure can also be obtained through the pressure detecting member mentioned above. Determine the target fluid pressure according to the downward pressure, and control the injection time of the power pump into the cavity k according to the difference between the real-time fluid pressure and the target fluid pressure. When the real-time fluid pressure reaches the target fluid pressure, it means that the supporting force provided by the fluid to the cold plate 40 is equivalent to the downward pressure, and then stop the power pump.

[0103] At this time, during the assembly process of the battery pack 100, control the power pump to input fluid into the cavity k according to the downward pressure exerted by the pressing mechanism 200 on the cold plate 40, so that the supporting force provided by the fluid is equivalent to the downward pressure, making the cold plate 40 evenly stressed up and down, the cold plate 40 is not prone to local depression, the thickness of the thermally conductive structural adhesive 30 filled between the cold plate 40 and the battery cell group 20 is uniform, the cold plate 40 and the battery cell group 20 can conduct heat evenly, and the thermal management effect of the battery pack 100 is better.

[0104] When there are multiple filling members 12 provided on the battery pack 100, the same power pump is independently connected to each filling member 12 and can synchronously convey fluid to each filling member 12.

[0105] Figure 11 It is a schematic flowchart of the debonding detection method for the battery pack 100 of some embodiments.

[0106] In addition, the present application also provides a debonding detection method for the battery pack 100, which is applied to the battery pack 100 in the above embodiments. The debonding detection method includes: P1. Monitoring the fluctuation of the supporting force provided by the fluid in the cavity k of the flexible member 50 to the cold plate 40; P2. When the fluctuation of the supporting force exceeds the allowable fluctuation range, determining that the battery pack 100 is debonded; P3. Outputting a debonding reminder message.

[0107] Specifically, after the battery pack 100 is assembled, during use, the battery management system (BMS) determines the supporting force situation provided by the fluid in the flexible member 50 through the above-mentioned pressure detection member. The supporting force can calculate the supporting force F received by the cold plate 40 according to the force P detected by the pressure detection member. The real-time calculated supporting force F can be compared with the pre-stored standard supporting force. If the difference exceeds the allowable range, it indicates that the battery pack 100 is debonded. If the difference does not exceed the allowable range, it indicates that the battery pack 100 is not debonded.

[0108] When it is determined that the battery pack 100 is debonded, the BMS can report a debonding prompt message to the electrical device (such as an automobile, an airplane) loading the battery pack 100, so as to give a timely warning reminder and improve the use reliability of the electrical device.

[0109] The debonding detection method for the battery pack 100 determines whether the battery pack 100 is debonded according to the fluctuation of the supporting force provided by the fluid in the flexible member 50 to the cold plate 40, can timely detect the abnormal situation of the battery pack 100, and improve the use reliability of the battery pack 100.

[0110] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0111] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A battery pack, characterized in that, include: The box body (10) includes a bottom guard plate (11); A battery cell group (20), a heat-conducting structural adhesive (30), and a cold plate (40) stacked in sequence along a Z direction, wherein the Z direction is a thickness direction of the bottom protective plate (11); and A flexible member (50) is arranged on the bottom guard plate (11) and supported on a side of the cold plate (40) away from the heat conductive structural adhesive (30); along the Z direction, the projection of the flexible member (50) overlaps with the projection of the battery cell group (20); a cavity (k) is constructed inside the flexible member (50), and a fluid is loaded in the cavity (k); the flexible member (50) is constructed to expand and contract with changes in the fluid content in the cavity (k) so as to adjust the supporting force of the flexible member (50) on the cold plate (40); and A filling member (12), the filling member (12) is in communication with the cavity (k) and can allow the fluid to enter and exit the cavity (k) so as to control the content of the fluid in the flexible member (50).

2. The battery pack according to claim 1, wherein, The flexible member (50) and the battery cell group (20) are both configured in plurality; in the Z direction, each battery cell group (20) is provided with a flexible member (50) in one-to-one correspondence; The filling pieces (12) are arranged in plurality, and the cavity (k) of each flexible piece (50) is independently connected to a filling piece (12) via a pipeline (G).

3. The battery pack according to claim 1, wherein The flexible member (50) comprises an elastically expandable support frame (51), and the cold plate (40) is supported by the support frame (51); The cavity (k) is located in the support frame (51), and the support frame (51) has an initial volume. When the fluid causes the volume of the cavity to exceed the initial volume, the support frame (51) is squeezed by the fluid to expand and increase its volume.

4. The battery pack according to claim 3, wherein The flexible member (50) further comprises an elastic bag (52) forming the cavity (k), wherein the elastic bag (52) is located in the support frame (51); the volume of the elastic bag (52) can change with the content of the fluid inside, and when the volume of the elastic bag (52) caused by the fluid exceeds the initial volume, the support frame (51) is squeezed by the elastic bag (52) to expand and increase its volume; A plurality of the elastic bags (52) are arranged in the support frame (51), and all the elastic bags (52) are sequentially spaced and arranged along the X direction, wherein the X direction is the length direction of the bottom guard plate (11); Each of the elastic bags (52) in the same support frame (51) is independently connected to the filling piece (12) via a pipeline (G).

5. The battery pack according to claim 4, characterized in that, The support frame (51) comprises a partition (53), and the partition (53) is separated between adjacent elastic bags (52); The partition portion (53) comprises a partition groove (53a) recessed in the outer surface of the support frame (51), and the partition groove (53a) is extended along a Y direction intersecting with the X direction, and the Y direction is the width direction of the bottom guard plate (11).

6. The battery pack according to claim 1, characterized in that, The battery cell group (20) includes an explosion-proof valve, the explosion-proof valve is located on one side of the battery cell group (20) facing the cold plate (40) along the Z direction, and the thermally conductive structural adhesive (30) avoids the explosion-proof valve; The cold plate (40) is provided with an avoidance portion (40a), the flexible member (50) is provided with a thinning portion (54), and the explosion-proof valve, the avoidance portion (40a) and the thinning portion (54) are arranged corresponding to each other along the Z direction; the avoidance portion (40a) and the thinning portion (54) are configured to be able to circulate the high-temperature and high-pressure flue gas released when the explosion-proof valve relieves pressure; The fluid filled in the cavity (k) includes a fire extinguishing substance, and the thinning portion (54) allows the high-temperature and high-pressure flue gas to enter the cavity (k) to be cooled by the fire extinguishing substance.

7. The battery pack according to claim 1, characterized in that, The filling member (12) includes a valve body (12e), a core body (12a), a thimble (12b) and a sealing plug (12c), the valve body (12e) has a through hole (e1), and the core body (12a), the thimble (12b) and the sealing plug (12c) are all arranged in the through hole (e1); A core cavity (a1) is provided in the core body (12a), the thimble (12b) passes through the core cavity (a1), and is movably arranged relative to the core body (12a) in the depth direction of the through hole (e1); The sealing plug (12c) is fixed to the thimble (12b) and can open and close the core cavity (a1) when moving with the thimble (12b).

8. The battery pack according to claim 1, wherein, The battery pack further includes a monitoring device and a pressure detection member, the pressure detection member is used to determine the supporting force provided by the fluid in the cavity (k) to the cold plate (40), and the monitoring device is communicatively connected to the pressure detection member for determining whether the battery pack is delaminated according to the detection result obtained by the pressure detection member.

9. A method for preparing a battery pack, applied to the battery pack according to any one of claims 1-8, characterized in that, The preparation method includes: During the process of pressing the battery cell group (20) into the box body (10) by using a pressing mechanism (200), detecting the downward pressure applied by the pressing mechanism (200) to the cold plate (40) through the battery cell group (20); According to the downward pressure, controlling a power pump connected to the filling member (12) to inject the fluid into the cavity (k) until the supporting force provided by the fluid in the cavity (k) of the flexible member (50) to the cold plate (40) is equivalent to the downward pressure.

10. A debonding detection method for a battery pack, applied to the battery pack according to any one of claims 1-8, characterized in that, The delamination detection method includes: Monitoring the fluctuation condition of the supporting force provided by the fluid in the cavity (k) of the flexible member (50) to the cold plate (40); When the fluctuation condition of the supporting force exceeds the allowable fluctuation range, determining that the battery pack is delaminated; Outputting a delamination prompt message.

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