Battery pack and system

Abstract

The utility model discloses a battery pack and a system, the battery pack comprises a shell and a battery cell module, the battery cell module is arranged in the shell, and the battery cell module comprises at least one battery cell; a piezoelectric foam composite body is additionally arranged between at least one battery cell and the battery cell or between the battery cell and the shell; the piezoelectric foam composite body comprises piezoelectric foam, electrode plates are arranged on the two sides of the piezoelectric foam, insulating films are arranged on the outer sides of the electrode plates, the piezoelectric foam can buffer deformation, and the piezoelectric foam and the electrode plates form a varistor. The piezoelectric foam composite body is arranged between the battery cells in the battery pack or between the battery cells and the shell, so that an enough expansion space can be effectively reserved for the expansion of the battery cells, and meanwhile, the expansion of the battery cells can be monitored in time. And on the basis of realizing real-time monitoring on the battery cell, the problems of poor structure integration level and lack of reserved expansion buffer space are solved.

Description

Technical Field

[0001] The utility model relates to the field of batteries, in particular to a battery pack and a system. Background Art

[0002] The battery packs of the prior art generally include a module housing and a plurality of battery cells arranged in series and / or in parallel within the module housing. Currently, generally, in order to improve the insulation between battery cells, an insulating film is added therebetween or the adjacent two battery cells are adhered by a foam. Using the foam to connect multiple battery cells improves the insulation of the battery cell module, and the foam can produce elastic deformation, playing a buffering role between adjacent battery cells and reserving a certain expansion space for the battery cells.

[0003] However, it can only passively cope with the deformation of the battery cells and cannot actively relieve the expansion of the battery cells. Through investigation, it is understood that those skilled in the art have also mentioned the research and development of actively preventing the expansion of battery cells. Generally, there are two ideas. One is to improve the positive electrode material, negative electrode material or electrolyte, etc. to reduce the expansion of the battery cells. The other is to monitor the expansion and control it within an acceptable range. For example, during the product sampling process, facilities for monitoring expansion are used to monitor the expansion results to ensure that the expansion is acceptable. But this method cannot monitor the expansion of the battery cells in real time.

[0004] As an improvement, patent CN117190841A mentions a method for real-time monitoring of battery cells, which is applied to the coulometer in the battery pack. The coulometer is communicatively connected to the pressure detection patch. The pressure detection patch is made of a microporous conductive elastic material. The pressure detection patch is attached to the battery cells of the battery pack. The method includes: collecting the current and voltage of the pressure detection patch at a preset sampling period, and calculating the patch resistance of the pressure detection patch at each sampling moment through the collected current and voltage; calculating the resistance change amount of each sampling period through the patch resistance at each sampling moment; calculating a resistance change rate sequence according to the resistance change amounts of two adjacent sampling periods; generating a warning message through the target moment when the target resistance change rate appears in the resistance change rate sequence. The warning message is used to warn that the battery cells expand at the target moment. The target resistance change rate is the resistance change rate that exceeds a preset numerical threshold compared to the resistance change rate of the previous sampling moment.

[0005] However, for the battery pack with the pressure detection patch attached to the battery cells to detect expansion, although it can achieve real-time monitoring of expansion, it lacks a buffer space for reserved expansion. At the same time, the structural integration degree is poor, and there is still room for further improvement. Summary of the Utility Model

[0006] The embodiments of the present utility model provide a battery pack and a system to solve the problems of poor structural integration and lack of reserved buffer space for expansion in the real-time monitoring of existing battery cells.

[0007] To solve the above problems, on the one hand, the embodiments of the present utility model provide a battery pack, including a housing and a battery cell module. The battery cell module is arranged in the housing, and the battery cell module includes at least one battery cell. Among them, a piezoelectric foam composite is arranged between at least one battery cell and another battery cell or between the battery cell and the housing. The piezoelectric foam composite includes piezoelectric foam, electrode plates are arranged on both sides of the piezoelectric foam, and an insulating film is arranged outside the electrode plates. The piezoelectric foam can buffer deformation, and the piezoelectric foam and the electrode plates form a piezoresistor.

[0008] Optionally, the electrode plates include a first electrode plate and a second electrode plate. The first electrode plate leads out a first electrode wire, and the second electrode plate leads out a second electrode wire.

[0009] Optionally, the first electrode plate and the second electrode plate are arranged in the orthographic projection on the upper and lower surfaces of the piezoelectric foam.

[0010] Optionally, the thickness of the first electrode plate and the second electrode plate is 0.003 - 1 mm.

[0011] Optionally, the piezoelectric foam includes a substrate and a conductive material dispersed in the substrate.

[0012] Optionally, the piezoelectric foam includes a conductive layer, and the conductive layer is a conductive foam.

[0013] Optionally, the substrate of the piezoelectric foam includes a non-Newtonian material layer.

[0014] Optionally, the thickness of the piezoelectric foam is 1 - 5 mm.

[0015] Optionally, the insulating film is integrally arranged.

[0016] To solve the above problems, on the other hand, the embodiments of the present utility model provide a battery pack system, including the above battery pack. In addition, it further includes a detection circuit. The detection circuit includes a signal source. The detection circuit is electrically connected to the electrode plates of the piezoelectric foam composite and is used to detect the resistance change between the electrode plates on both sides of the piezoelectric foam.

[0017] By providing a piezoelectric foam composite between battery cells or between a battery cell and the housing within a battery pack, sufficient expansion space can be effectively reserved for the expansion of the battery cells. Meanwhile, the expansion of the battery cells can be monitored in a timely manner. When the expansion exceeds a preset expansion threshold, the charging or discharging circuit can be cut off immediately, putting the battery cell in an open circuit state. On the basis of realizing real-time monitoring of the battery cells, the problems of poor structural integration and lack of reserved buffer space for expansion are solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for the description of the embodiments of the present invention. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 is a schematic diagram of a battery cell module in an embodiment of the present invention Figure 1 ;

[0020] Figure 2 is a schematic diagram of a piezoelectric foam composite in an embodiment of the present invention;

[0021] Figure 3 is a schematic diagram of a battery cell module in an embodiment of the present invention Figure 2 ;

[0022] Figure 4 is a schematic diagram of the piezoelectric foam composite in an unloaded state in an embodiment of the present invention;

[0023] Figure 5 is a schematic diagram of the piezoelectric foam composite in a state of being squeezed and deformed in an embodiment of the present invention;

[0024] Figure 6 is a schematic diagram of a battery cell module in an embodiment of the present invention Figure 3 ;

[0025] Figure 7 is a schematic diagram of the lamination of the piezoelectric foam composite in an embodiment of the present invention Figure 1 ;

[0026] Figure 8 is a schematic diagram of the lamination of the piezoelectric foam composite in an embodiment of the present invention Figure 2 ;

[0027] Figure 9 is a schematic diagram of a detection circuit in an embodiment of the present invention.

[0028] The reference numerals in the specification are as follows:

[0029] 100, Battery cell module;

[0030] 200, Piezoelectric foam composite;

[0031] 300, Detection circuit;

[0032] 1, Battery cell; 2, Piezoelectric foam; 3, First electrode sheet; 4, Second electrode sheet; 5, First insulating film; 6, Second insulating film; 7, First electrode wire; 8, Second electrode wire. Detailed implementation mode

[0033] In order to make the technical problems, technical solutions and beneficial effects solved by the present utility model clearer, the present utility model will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0034] In order to solve the problems of poor structural integration and lack of reserved expansion buffer space in the existing pressure detection method attached to the battery cell, on the one hand, the present utility model proposes a battery pack.

[0035] As Figures 1 to 9 shown, the battery pack includes a housing (not shown) and a battery cell module 100. The battery cell module 100 is arranged in the housing. The battery cell module 100 includes at least one battery cell 1. Among them, a piezoelectric foam composite 200 is arranged between at least one battery cell 1 and another battery cell 1 or between a battery cell 1 and the adjacent housing. In this embodiment, as Figure 1 shown, a piezoelectric foam composite 200 is arranged between each battery cell 1 and the battery cell 1. The piezoelectric foam composite 200 includes a piezoelectric foam 2. Electrode sheets are arranged on both sides of the piezoelectric foam 2, and insulating films are arranged outside the electrode sheets.

[0036] The electrode sheets include a first electrode sheet 3 and a second electrode sheet 4. The first electrode sheet 3 and the second electrode sheet 4 are arranged in the orthographic projection on the upper and lower surfaces of the piezoelectric foam 2. A first electrode wire 7 is led out from the first electrode sheet 3, and a second electrode wire 8 is led out from the second electrode sheet 4.

[0037] The materials of the first electrode sheet 3 and the second electrode sheet 4 are copper sheets, and the thickness is 0.003 - 1 mm. A first insulating film 5 is arranged outside the first electrode sheet 3, and a second insulating film 6 is arranged outside the second electrode sheet 4.

[0038] The piezoelectric foam 2 is electrically conductive. One way to achieve conductivity is to add a conductive material to the substrate of the piezoelectric foam 2, and the conductive material is dispersed in the substrate. For example, metal powders such as copper powder and nickel powder are added to improve the conductivity of the foam. Another example is to add carbon black, a commonly used conductive additive, which has excellent conductivity and stability. In addition, silver paste can also be added. Silver has excellent conductivity and can significantly improve the conductive effect of the foam.

[0039] Another way for the piezoelectric foam 2 to achieve conductivity is to provide a conductive layer in the piezoelectric foam. The conductive layer is a conductive foam, and the conductive foam includes materials such as conductive cloth and conductive fiber. The conductive foam is usually made by wrapping the conductive cloth around a flame-retardant sponge. The conductive cloth itself is woven from conductive materials (such as metal fibers and carbon fibers) and has good conductivity.

[0040] As an implementation method, the substrate of the piezoelectric foam 2 includes component A and component B. Component A and component B are prepared according to the molar ratio of hydroxyl group to isocyanate group in the curing agent of 1:1 - 1.05. The raw materials of component A and component B are mixed at high speed (at a rotation speed of 4000 - 7000 rpm), injected into the mold cavity, and the mold is closed and locked. A polymerization reaction occurs in the mold cavity for several minutes at 45 - 65 °C, foaming and filling the entire mold cavity. The mold is opened to take out the product.

[0041] The thickness of the piezoelectric foam 2 is 1 - 5 mm, and the density of the substrate is 0.2 - 1.5 g / cm3.

[0042] As Figure 4 and Figure 5 shown, the piezoelectric foam composite 200 does not deform when not under force. When the battery cell 1 expands, the battery cell 1 squeezes the piezoelectric foam composite 200 to cause it to deform. The piezoelectric foam 2 can buffer the deformation. At the same time, the first electrode sheet 3, the piezoelectric foam 2, and the second electrode sheet 4 form a piezoresistor. When a weak voltage is applied across the first electrode sheet 3 and the second electrode sheet 4, the resistance change of the piezoelectric foam composite 200 can be detected, and then the change amount of the expansion of the battery cell 1 can be obtained.

[0043] As an implementation method, the substrate of the piezoelectric foam 2 includes a non-Newtonian material layer.

[0044] As an implementation method, as Figure 6 shown, the piezoelectric foam composite 200 can be provided only between two certain battery cells 1 in the battery cell module 100.

[0045] As an implementation method, as Figure 8 shown, the first insulating film 5 and the second insulating film 6 cover the upper and lower surfaces of the piezoelectric foam 2.

[0046] As an implementation manner, the insulating film can be integrally provided to wrap the piezoelectric foam 2 in a wrapping form to cover the electrode sheet.

[0047] On the other hand, an embodiment of the present utility model provides a battery pack system, including the above-mentioned battery pack. In addition, it further includes a detection circuit 300. The detection circuit 300 includes a signal source, such as a voltage source or a current source. The detection circuit 300 is electrically connected to the electrode sheets of the piezoelectric foam composite, and is used to detect the resistance change between the electrode sheets on both sides of the piezoelectric foam. Specifically, the detection circuit 300 is connected to the first electrode wire 7 and the second electrode wire 8. When a weak voltage is applied to both sides of the first electrode sheet 3 and the second electrode sheet 4 through the first electrode wire 7 and the second electrode wire 8, the resistance change of the piezoelectric foam composite 200 can be detected, and then the change amount of the expansion of the battery cell 1 can be obtained. By arranging the piezoelectric foam composite between the battery cells in the battery pack or between the battery cell and the housing, an effective expansion space can be reserved for the expansion of the battery cell, and at the same time, the expansion of the battery cell can be monitored in a timely manner. When it exceeds the preset expansion threshold, the charging or discharging circuit can be cut off immediately, so that the battery cell is in an open circuit state. On the basis of realizing the real-time monitoring of the battery cell, the problems of poor structural integration and lack of reserved expansion buffer space are solved.

[0048] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "radial", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model 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 therefore should not be construed as a limitation to the present utility model. In the description of the present utility model, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0049] In the description of the present utility model, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; 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. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0050] The above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A battery pack, characterized in that: It comprises a shell and a battery cell module, wherein the battery cell module is arranged in the shell, and the battery cell module comprises at least one battery cell; wherein a piezoelectric foam composite is added between at least one battery cell and the battery cell or between the battery cell and the shell; the piezoelectric foam composite comprises piezoelectric foam, electrode sheets are arranged on both sides of the piezoelectric foam, an insulating film is arranged on the outer side of the electrode sheet, the piezoelectric foam can buffer deformation, and the piezoelectric foam and the electrode sheet constitute a variable resistor.

2. The battery pack according to claim 1, characterized in that: The electrode sheet includes a first electrode sheet and a second electrode sheet, the first electrode sheet leads to a first electrode wire, and the second electrode sheet leads to a second electrode wire.

3. The battery pack according to claim 2, characterized in that: The first electrode sheet and the second electrode sheet are arranged on the upper and lower surfaces of the piezoelectric foam in an orthogonal projection manner.

4. The battery pack according to claim 3, characterized in that: The thickness of the first electrode sheet and the second electrode sheet is 0.003-1 mm.

5. The battery pack according to claim 1, characterized in that: The piezoelectric foam includes a substrate and a conductive material dispersed in the substrate.

6. The battery pack according to claim 1, characterized in that: The piezoelectric foam comprises a substrate layer and a conductive layer, and the conductive layer is conductive foam.

7. The battery pack according to claim 1, characterized in that: The substrate of the piezoelectric foam includes a non-Newtonian material layer.

8. The battery pack according to claim 1, characterized in that The thickness of the piezoelectric foam is 1-5 mm.

9. The battery pack according to claim 1, characterized in that: The insulating film is integrally arranged.

10. A battery pack system, characterized in that: A battery pack comprising any one of claims 1 to 9, further comprising a detection circuit, wherein the detection circuit comprises a signal source, and the detection circuit is electrically connected to the electrode sheets of the piezoelectric foam composite, and is used to detect the resistance change between the electrode sheets on both sides of the piezoelectric foam.

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