Battery pack with function of monitoring expansion of battery cell

Abstract

The utility model discloses a kind of battery pack with battery swelling monitoring function, including shell, multiple battery and strain fiber;The shell includes box, upper cover plate, lower cover plate;Box is provided with swelling beam, the space of the box is divided into battery space and equipment space;Battery is arranged in battery space with horizontal array mode, forms battery array;Strain fiber at least includes first strain fiber and second strain fiber;First strain fiber is located along the length direction of the swelling beam in the side of equipment space, and forms multiple swelling measuring points;Second strain fiber is fixed in the inside of upper cover plate in serpentine mode, traverses entire battery array, and forms multiple swelling measuring points;The connection of grating measuring point and the shell is tight rigid connection;Battery and shell are filled between by structural adhesive.This battery pack uses fiber grating sensing technology, can monitor the swelling condition of battery pack, substantially does not occupy battery pack space, does not affect original structure of battery pack.

Description

Technical Field

[0001] This utility model relates to the field of battery failure management technology, and in particular to a battery pack with cell expansion monitoring function. Background Technology

[0002] Currently, there are no means to monitor the deformation of the structural components of the battery pack. External compression and impact, as well as the expansion of the battery pack (square or pouch), can cause deformation of the battery pack structure. If the sealed interface of the battery pack is subjected to compression and impact, it is easy to cause airtightness failure, which can eventually lead to insulation failure or even fire and explosion. During use, the cells will continue to collide with the outside as their lifespan progresses until the end of their lifespan. The collisions of the cells will act on the structural beams of the battery pack. Therefore, monitoring the expansion and deformation of the beams or cells can directly characterize the lifespan of the cells and further improve the safety of the battery pack. However, current technology does not have this aspect of monitoring.

[0003] Currently, the lifespan assessment of battery pack cells is based on estimations using parameters such as voltage and current, which introduces certain errors and cannot accurately characterize cell lifespan in real time. Utility Model Content

[0004] This utility model aims to provide a battery pack with a cell expansion monitoring function, which can monitor the deformation of the battery pack structure caused by cell expansion and external impact. The technical solution is as follows:

[0005] A battery pack with cell expansion monitoring function includes a housing, multiple cells, and strain optical fiber;

[0006] The housing includes a box body, an upper cover plate, and a lower cover plate; the box body is provided with an expansion beam, which divides the box body space into a battery space and a device space.

[0007] The battery cells are arranged in a horizontal array in the battery space to form a battery cell array; their positive and negative terminals are arranged vertically, facing the upper cover plate and the lower cover plate;

[0008] The grating measurement points of the strained optical fiber are generated by holographic coherence or phase template mask exposure.

[0009] The strained optical fiber includes at least a first strained optical fiber and a second strained optical fiber; one end of the strained optical fiber is suspended, and the other end is connected to the device space or led out from the housing through an optical fiber connector;

[0010] The first strain fiber is arranged along the length direction of the expansion beam on one side of the equipment space, and the multiple fiber measuring points of the first strain fiber correspond one-to-one with the multiple expansion measuring points calibrated on the expansion beam.

[0011] The second strain fiber is fixed to the inside of the upper cover plate in a serpentine manner, traversing the entire cell array. Multiple grating measurement points on the second strain fiber correspond one-to-one with multiple expansion measurement points calibrated by the cell array.

[0012] The connection between the grating measurement point of the strain fiber and the housing is a tight, rigid connection.

[0013] The space between the battery cell and the housing is filled with structural adhesive.

[0014] Furthermore, a strain measurement point is marked on the upper surface of each cell.

[0015] Furthermore, it also includes a third strain fiber, which is fixed in a serpentine manner to the inner side of the lower cover plate and traverses the entire cell array. Multiple grating measurement points on the third strain fiber correspond one-to-one with multiple collision measurement points calibrated by the cell array.

[0016] Furthermore, the calibration spacing of the collision measurement points is 50mm to 120mm.

[0017] Furthermore, the strain fiber is routed to avoid the positive and negative terminals of the battery cell, and the grating measurement points are arranged to avoid the bends in the fiber route, with the bend radius of the fiber route being greater than or equal to 50mm.

[0018] Furthermore, the grating length of the grating measurement point of the strain fiber is no greater than 1 mm.

[0019] Furthermore, the grating measuring point armored metal sleeve of the strain optical fiber is rigidly connected to the shell by welding.

[0020] Compared with the prior art, the significant features of this utility model are:

[0021] (1) Using fiber optic grating sensing technology, it can monitor the stress changes caused by the thermal expansion and contraction of the cells in the battery pack, monitor the expansion of the battery pack at multiple points, and quickly locate the expansion points.

[0022] (2) It is small in size and does not take up much space in the battery pack, nor does it affect the original structure of the battery pack.

[0023] (3) No electrical sensors are introduced into the entire battery pack, so there is no risk of insulation failure. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the battery pack structure of this utility model; (suggested) Figure 1 Add one strain fiber and place it between the upper cover plate 2 and the box 1 for expansion monitoring.

[0025] Figure 2 This is a diagram showing the strain fiber arrangement of the expansion beam;

[0026] Figure 3 This is a diagram showing the arrangement of fiber optic measuring points on the upper cover plate using strain gauges.

[0027] Figure 4 This is a diagram showing the arrangement of fiber optic measuring points on the lower cover plate of the strain gauge fiber. Detailed Implementation

[0028] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention and are mainly used to illustrate the embodiments, and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention. Components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0029] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0030] like Figure 1 As shown, this utility model provides an embodiment of a battery pack with cell expansion monitoring function, including a housing (assembled from a casing 1, an upper cover plate 2, a lower cover plate 3, etc.), battery cells 4, and strain gauge optical fibers 5, 6, and 10. The casing 1 is divided into a battery space 8 and an equipment space 9 by an expansion beam 7. The battery cells 4 are placed in an array in the battery space 8 to form a battery cell array. After the battery cell array is electrically connected, it is filled and fixed with structural adhesive. The equipment space 9 can be used to house electrical units such as a battery management system (BMS).

[0031] like Figure 2 As shown, in the specific arrangement, the strain fiber 5 is arranged on the outside of the expansion beam 7 (i.e., on one side of the equipment space 9), along the length of the expansion beam 7, and the connection between the grating measurement points 11 of the strain fiber 5 and the expansion beam 7 is a tight, rigid connection. The higher the density of the grating measurement points 11 in the strain fiber 5, the higher the spatial resolution of the expansion beam's deformation; by identifying the position of the connection point, the deformation of the entire expansion beam can be fitted.

[0032] like Figure 3As shown, the strain fiber 6 is arranged in a serpentine pattern inside the upper cover plate 2, traversing the entire upper surface of the cell array. Multiple grating measurement points 12 on the strain fiber 6 correspond one-to-one with multiple expansion measurement points calibrated in the cell array, and the connection between the grating measurement points 12 of the strain fiber 6 and the upper cover plate 2 is a tight, rigid connection. The strain fiber 6 is mainly used for expansion detection. The higher the density of the grating measurement points 12 in the strain fiber 6, the higher the spatial resolution of the deformation on the upper surface of the battery pack; by identifying the position of the connection point, the deformation of the entire upper surface of the battery pack can be fitted. Preferably, one expansion measurement point is set on each cell 4, and the position of each grating measurement point 12 in the strain fiber 6 is calibrated according to the distance between the cells 4.

[0033] like Figure 4 As shown, the strain fiber 10 is arranged inside the lower cover plate 3 using a serpentine routing method, traversing the entire lower surface of the battery cell array. Multiple grating measurement points 13 on the strain fiber 10 correspond one-to-one with multiple expansion measurement points calibrated on the battery cell array, and the connection between the grating measurement points 13 of the strain fiber 10 and the lower cover plate 3 is a tight, rigid connection. The strain fiber 10 is mainly used for collision detection. When the battery pack experiences a collision, the bottom of the battery pack undergoes severe deformation, at which point fiber breakage or abnormal light emission can be detected.

[0034] In the specific arrangement, the strain gauge fibers 6 and 10 need to be positioned to avoid the positive and negative poles and explosion-proof valves. Simultaneously, the grating placement needs to avoid bends in the fiber optic cable routing, as shown in area A. Preferably, the bend radius of the fiber optic cable routing needs to be greater than or equal to 50mm to reduce signal attenuation caused by light leakage.

[0035] In this embodiment, the grating measurement points 11, 12, and 13 of the strain fibers 5, 6, and 10 are generated by holographic coherence or phase template mask exposure. The actual length of each grating measurement point is less than or equal to 1 mm, and the distance between the grating measurement points can be infinitely close. It can be appropriately adjusted according to the spatial resolution requirements of the actual application and the cost of the equipment (more points require higher frequency and resolution of the acquisition equipment). Preferably, for performing bottom impact detection, the calibration spacing between adjacent grating measurement points 13 is 50 mm to 120 mm.

[0036] Strained optical fibers can be deployed at increased density as needed, forming a network both horizontally and vertically through methods such as serpentine routing.

[0037] In this embodiment, the battery space 8 between the casing and the cell array is filled with structural adhesive. The thermal expansion of the cell can be conducted to the top cover plate 2 and the expansion beam 7 through the structural adhesive, resulting in deformation.

[0038] Preferably, the grating measurement point and the housing of the strain fiber can be rigidly connected by structural adhesive, or a metal sleeve can be fitted at the grating measurement point of the strain fiber and rigidly connected by welding.

[0039] The cell expansion monitoring function of this battery pack is implemented in the following way:

[0040] One end of the strain fiber is suspended in the air, and the other end is introduced into the device space 8 or led out from the battery pack through the fiber optic connector and connected to devices such as the grating demodulator to analyze the fiber reflection signal.

[0041] The fiber optic time-domain measurement unit (ODTR) sends a laser sweep signal to the strain fiber and simultaneously receives the reflected signal. Since each grating has a different reflection wavelength, the wavelength of the reflected signal can be identified to correspond to a specified expansion measurement point (or collision measurement point). Then, based on the offset of the reflected wavelength, the expansion level of that measurement point can be monitored. Once the ODTR completes one sweep test, the expansion level of each expansion measurement point on the battery pack can be monitored in real time.

[0042] Based on the expansion levels at various expansion measurement points of the battery pack, it can be applied to applications such as battery pack fault analysis and lifespan analysis. For example, the lifespan of the battery pack can be correlated with the expansion level of the battery pack, and the relationship curve between the two can be fitted. The lifespan of the battery pack can be estimated based on the expansion level or average expansion level of each block of the battery pack.

[0043] Compared with the prior art, the significant features of this utility model are:

[0044] (1) Using fiber optic grating sensing technology, it can monitor the stress changes caused by the thermal expansion and contraction of the cells in the battery pack, monitor the expansion of the battery pack at multiple points, and quickly locate the expansion points.

[0045] (2) It is small in size and does not take up much space in the battery pack, nor does it affect the original structure of the battery pack.

[0046] (3) No electrical sensors are introduced into the entire battery pack, so there is no risk of insulation failure.

[0047] Although the present invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the present invention without departing from the spirit and scope of the present invention as defined in the appended claims, and all such changes shall be within the scope of protection of the present invention.

Claims

1. A battery pack with cell expansion monitoring function, characterized in that, The shell, a plurality of battery cells and a strain fiber are included. The shell comprises a box, an upper cover plate and a lower cover plate. The box is provided with an expansion beam, which divides the box space into a battery space and a device space. The battery cells are arranged in a horizontal array in the battery space to form a battery cell array. The positive and negative electrode posts of the battery cells are arranged vertically and face the upper and lower cover plates. The grating measuring points of the strain fiber are generated by holographic coherence or phase mask exposure. The strain fiber comprises at least a first strain fiber and a second strain fiber. One end of the strain fiber is suspended, and the other end is connected to the device space or drawn out of the shell through a fiber connector. The first strain fiber is arranged along the length direction of the side of the expansion beam in the device space. The plurality of fiber measuring points of the first strain fiber correspond to the plurality of expansion measuring points of the expansion beam.

2. The battery pack having a function of monitoring swelling of an electrode according to claim 1, wherein The second strain fiber is fixed to the inner side of the upper cover plate in a serpentine manner and traverses the entire battery cell array.

3. The battery pack having a function of monitoring swelling of an electrode according to claim 1, wherein The plurality of grating measuring points on the second strain fiber correspond to the plurality of expansion measuring points of the battery cell array.

4. The battery pack having a function of monitoring swelling of an electrode according to claim 3, wherein The connection between the grating measuring points of the strain fiber and the shell is a tight and rigid connection.

5. The battery pack having a function of monitoring swelling of an electrode according to claim 1, wherein The structure glue is filled between the battery cells and the shell.

6. The battery pack having a function of monitoring swelling of an electrode according to claim 1, wherein An upper surface of each battery cell is marked with a strain measuring point.

7. The battery pack having a function of monitoring swelling of an electrode according to claim 1, wherein A third strain fiber is also included. The third strain fiber is fixed to the inner side of the lower cover plate in a serpentine manner and traverses the entire battery cell array. The plurality of grating measuring points on the third strain fiber correspond to the plurality of collision measuring points of the battery cell array. The marking distance of the collision measuring points is 50mm-120mm. The routing of the strain fiber avoids the positive and negative electrode posts of the battery cells. The grating measuring point arrangement position avoids the bending position of the fiber routing, and the bending radius of the fiber routing is greater than or equal to 50mm. The length of the grating measuring point is not greater than 1mm. The surface of the strain fiber is armored with a metal sleeve, which is rigidly connected to the shell by welding.

Images