Battery pack, battery pack control method and vehicle

Abstract

This disclosure relates to a battery pack, a control method for the battery pack, and a vehicle. The battery pack includes a housing, individual battery cells, a control component, and a control system. Both the individual battery cells and the control component are housed within the housing. The control component has a control cavity and abuts against the individual battery cells to apply pressure to them. The control system is connected to the control cavity to adjust the pressure within the control cavity. The battery pack of this disclosure, by providing a control system connected to the control cavity of the control component, can adjust the pressure applied to the individual battery cells by regulating the pressure within the control cavity. This allows for adjustment of the thickness of the individual battery cells, and consequently, the expansion force of the individual battery cells. This improves the performance and extends the lifespan of the individual battery cells, thereby improving the performance and extending the lifespan of the entire battery pack.

Description

Technical Field

[0001] This disclosure relates to the field of power battery technology, specifically to a battery pack, a control method for the battery pack, and a vehicle. Background Technology

[0002] The expansion force of individual battery cells in a battery pack is closely related to their performance and lifespan. Controlling the expansion force of individual battery cells within a battery pack is a problem that urgently needs to be solved. Summary of the Invention

[0003] This disclosure proposes a battery pack that can adjust the expansion force of individual battery cells, thereby improving the performance of the battery pack and extending its service life.

[0004] The battery pack disclosed herein includes a housing, battery cells, a control component, and a control system. The battery cells and the control component are both disposed within the housing. The control component has a control cavity and abuts against the battery cells to apply pressure to the battery cells. The control system is connected to the control cavity to adjust the pressure of the control cavity.

[0005] Optionally, the control unit is further provided with a heat exchange chamber for the flow of heat exchange medium to exchange heat with the battery cell.

[0006] Optionally, the control element is attached to the battery cell.

[0007] Optionally, the battery cell includes multiple outer surfaces, at least one of which is a contact surface; the battery cell includes an electrode, at least a portion of which is parallel to the thickness direction of the electrode, and the control element is in contact with the contact surface.

[0008] Optionally, the control cavity includes a plurality of first walls, with adjacent first walls intersecting; and / or, the heat exchange cavity includes a plurality of second walls, with adjacent second walls intersecting.

[0009] Optionally, the control chamber and the heat exchange chamber are arranged alternately.

[0010] Optionally, the control element is disposed on at least one side of the battery cell in a first direction, and the heat exchange cavity and the control cavity are alternately arranged along a second direction, which is perpendicular to the first direction.

[0011] Optionally, the control element is disposed on opposite sides of the battery cell in the first direction.

[0012] Optionally, the battery cell has a first cross-section cut by a plane perpendicular to a third direction, and the control element has a second cross-section cut by a cross-section perpendicular to a third direction, wherein the third direction is perpendicular to both the first and second directions; the area of ​​the first cross-section is S1, and the area of ​​the second cross-section is S2, wherein S1 > 6 * S2.

[0013] Optionally, the control element has a second cross section cut by a section perpendicular to a third direction, and the heat exchange cavity has a third cross section cut by a section perpendicular to a third direction, the third direction being perpendicular to the first direction and the second direction; the area of ​​the second cross section is S2, and the area of ​​the third cross section is S3, wherein S2 < 2*S3, and S2 > 1.05*S3.

[0014] Optionally, the heat exchange cavity has a third cross section cut by a section perpendicular to a third direction, and the control cavity has a fourth cross section cut by a section perpendicular to a third direction, the third direction being perpendicular to the first direction and the second direction; the area of ​​the third cross section is S3, and the area of ​​the fourth cross section is S4, wherein S3 < 10 * S4, and S3 > 2 * S4.

[0015] Optionally, the control element has a second cross section cut by a section perpendicular to a third direction, and the control cavity has a fourth cross section cut by a section perpendicular to a third direction, the third direction being perpendicular to the first direction and the second direction; the area of ​​the second cross section is S2, and the area of ​​the fourth cross section is S4, wherein S2 < 20 * S4, and S2 > 3 * S4.

[0016] Optionally, the control system includes a medium supply device and a pressure regulating device. The medium supply device is connected to the control cavity to provide a control medium to the control cavity, and the pressure regulating device is connected to the medium supply device to regulate the pressure of the control medium flowing from the medium supply device into the control cavity.

[0017] Optionally, the medium supply device is an air compressor, and the pressure regulating device is a pressure regulating valve; or, the medium supply device is a pressure storage tank, and the pressure regulating device is a pressure pump.

[0018] This disclosure also proposes a method for controlling a battery pack.

[0019] The battery pack control method disclosed herein includes:

[0020] The control system obtains the state of equilibrium (SOH) and / or state of charge (SOC) of the battery pack, and adjusts the pressure of the control chamber to make the pressure of at least one of the battery cells, the heat exchange chamber, and the control chamber the corresponding target pressure.

[0021] Optionally, when the SOH is greater than or equal to 95%, the control system adjusts the pressure of the control chamber to make the pressure of the battery cell the corresponding target pressure.

[0022] Optionally, when the SOH is less than 60%, the control system adjusts the control chamber to an open state or the pressure of the control chamber to zero.

[0023] Optionally, when the SOH is less than 95% and greater than or equal to 60%, and the pressure of the battery cell is greater than the pressure of the heat exchange chamber, the control system adjusts the pressure of the control chamber to make the pressure of the control chamber less than the pressure of the heat exchange chamber.

[0024] When the SOH is less than 95% and greater than or equal to 60%, and the pressure of the battery cell is less than the pressure of the heat exchange chamber, the control system adjusts the pressure of the control chamber to make the pressure of the battery cell the corresponding target pressure.

[0025] Optionally, when the SOC is greater than or equal to a preset value, the control system adjusts the pressure of the control cavity to reduce the pressure of the battery cell so that the pressure of the battery cell is the corresponding target pressure.

[0026] When the SOC is less than a preset value, the control system adjusts the pressure of the control cavity to increase so that the pressure of the battery cell is the corresponding target pressure.

[0027] This disclosure also proposes a vehicle.

[0028] The vehicles disclosed herein include the battery pack described in any of the foregoing.

[0029] The battery pack disclosed herein uses a control component installed within the housing to abut against individual battery cells, applying pressure to the cells. A control system connected to the control chamber of the control component regulates the pressure within the chamber, thereby adjusting the pressure applied to the battery cells and consequently, the thickness and expansion force of each cell. This improves the performance and extends the lifespan of the individual battery cells, ultimately enhancing the overall performance and lifespan of the battery pack. Attached Figure Description

[0030] Figure 1 This is a partial structural schematic diagram of the battery pack according to an embodiment of the present disclosure.

[0031] Figure 2 This is a partial cross-sectional view of a battery pack according to an embodiment of this disclosure.

[0032] Figure 3 yes Figure 2A sectional view of the control component.

[0033] Figure label:

[0034] 1. Battery cell; 11. Contact surface;

[0035] 2. Control component; 21. Control cavity; 211. First wall surface; 22. Heat exchange cavity; 221. Second wall surface;

[0036] 3. Control system; 31. Media supply device; 32. Pressure regulating device;

[0037] 4. End plate; 41. First end plate; 42. Second end plate. Detailed Implementation

[0038] Embodiments of this disclosure are described in detail below, with examples of these embodiments illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this disclosure, and should not be construed as limiting it.

[0039] Experimental studies have revealed that the expansion force of a single battery cell is closely related to its thickness. Therefore, by adjusting the thickness of a single battery cell, its expansion force can be controlled, thereby improving its performance and extending its lifespan, which in turn improves the performance and extends the lifespan of the entire battery pack. The thickness of a single battery cell is influenced by both its own internal conditions, such as the internal pressure, and by external forces exerted upon it, such as those applied by external components. Therefore, by adjusting the external forces applied to the battery cell, its thickness can be adjusted, and consequently, its expansion force can be controlled.

[0040] like Figures 1 to 3 As shown, the battery pack of this embodiment includes a housing, battery cells 1, a control component 2, and a control system 3. Both the battery cells 1 and the control component 2 are housed within the housing. The control component 2 has a control cavity 21 and abuts against the battery cells 1 to apply pressure to them. The control system 3 is connected to the control cavity 21 and is used to adjust the pressure in the control cavity 21, thereby adjusting the pressure applied to the battery cells 1 by the control component 2.

[0041] The battery pack of this embodiment uses a control member 2 installed inside the housing to abut against the battery cells 1, applying pressure to the battery cells 1. A control system 3 connected to the control cavity 21 of the control member 2 is provided. By adjusting the pressure in the control cavity 21 using the control system 3, the pressure applied to the battery cells 1 by the control member 2 can be adjusted, thereby adjusting the thickness of the battery cells 1 and consequently, the expansion force of the battery cells 1. This improves the performance of the battery cells 1 and extends their lifespan, thereby improving the performance of the battery pack and extending its lifespan.

[0042] In some embodiments, the thickness direction of the battery cell 1 can be understood as the direction of the external force applied to the battery cell 1 by the control element 2.

[0043] In some embodiments, the control system 3 includes a medium supply device 31 and a pressure regulating device 32. The medium supply device 31 is connected to the control cavity 21 to provide a control medium to the control cavity 21. The pressure regulating device 32 is connected to the medium supply device 31 to regulate the pressure of the control medium flowing from the medium supply device 31 into the control cavity 21.

[0044] Understandably, the control medium can be fluids such as water or gas.

[0045] Specifically, when adjusting the pressure of the control chamber 21, the medium supply device 31 supplies the control medium to the control chamber 21, and the pressure regulating device 32 adjusts the pressure of the control medium flowing into the control chamber 21, so that the control medium with a preset pressure enters the control chamber 21, thereby achieving pressure regulation of the control chamber 21. The preset pressure is equal to the target pressure of the control chamber 21; that is, if the pressure regulation of the control chamber 21 needs to be P, the pressure regulating device 32 adjusts the pressure of the control medium flowing into the control chamber 21 to P.

[0046] By injecting a control medium with a preset pressure into the control cavity 21, the pressure regulation of the control cavity 21 can be achieved. This not only makes it easier to regulate the pressure of the control cavity 21, but also makes the control component 2 lighter, which helps to reduce the weight of the battery pack.

[0047] In some other embodiments, when the control chamber 21 is water, the pressure of the control chamber 21 can be controlled by controlling the flow rate of the water.

[0048] Optionally, the control medium is gas, the medium supply device 31 is an air compressor, and the pressure regulating device 32 is a pressure regulating valve.

[0049] When adjusting the pressure of the control chamber 21, an air compressor is used to compress the air and supply the compressed air to the control chamber 21. The pressure of the gas flowing into the control chamber 21 is adjusted by a pressure regulating valve to achieve pressure regulation of the control chamber 21.

[0050] The medium supply device 31 is an air compressor, which can avoid the battery pack itself carrying an air source, and is conducive to further reducing the weight of the battery pack.

[0051] In other embodiments, the control medium is gas, the medium supply device 31 is a pressure storage tank, and the pressure regulating device 32 is a pressure pump.

[0052] When adjusting the pressure of the control chamber 21, compressed air is supplied to the control chamber 21 by using a pressure tank, and the pressure of the gas flowing into the control chamber 21 is adjusted by using a pressure pump to achieve pressure regulation of the control chamber 21.

[0053] By setting the medium supply device 31 as a pressure tank, the air source in the pressure tank can be used directly, which is conducive to quickly realizing the pressure regulation of the control chamber 21, and conveniently adjusting the expansion force of the battery cell 1 as needed, thereby further improving the performance of the battery pack and extending its service life.

[0054] In some embodiments, such as Figure 3 As shown, the control unit 2 is also provided with a heat exchange chamber 22 for the flow of heat exchange medium, so that the control unit 2 can exchange heat with the battery cell 1. The heat exchange medium can be water, oil, liquid carbon dioxide or air, etc.

[0055] For example, the control unit 2 is also provided with a medium inlet and a medium outlet. Both the medium inlet and the medium outlet are connected to the heat exchange chamber 22. The heat exchange medium enters the heat exchange chamber 22 through the medium inlet, then flows in the heat exchange chamber 22 and exchanges heat with the battery cell 1. Finally, the heat exchange medium flows out through the medium outlet.

[0056] By providing a heat exchange chamber 22 on the control unit 2, and utilizing the heat exchange medium flowing within the heat exchange chamber 22 to exchange heat with the battery cell 1, heating or cooling of the battery cell 1 can be achieved. This keeps the battery cell 1 within a suitable operating temperature range, which is beneficial for improving the performance and safety of the battery pack.

[0057] Optionally, the control element 2 can be a heat exchange plate.

[0058] For example, the control component 2 is a harmonica tube plate, one part of the chamber of the harmonica tube plate is the control chamber 21, and the other part of the chamber of the harmonica tube plate is the heat exchange chamber 22.

[0059] Optionally, such as Figure 1 and Figure 2 As shown, the control component 2 is attached to the battery cell 1.

[0060] For example, the control component 2 is directly attached to the surface of the battery cell 1, or the control component 2 is attached to the surface of the battery cell 1 through thermally conductive adhesive.

[0061] By attaching the control component 2 to the battery cell 1, the thermal resistance between the control component 2 and the battery cell 1 can be reduced, the heat exchange efficiency between the control component 2 and the battery cell 1 can be improved, and the performance and safety of the battery pack can be further improved.

[0062] Optionally, such as Figure 2 As shown, the battery cell 1 includes multiple outer surfaces, at least one of which is a contact surface 11. The battery cell 1 includes an electrode, at least a portion of which is parallel to the surface of the electrode in terms of thickness, and the control member 2 is attached to the contact surface 11.

[0063] Wherein, at least a portion of the contact surface 11 is parallel to the surface in terms of electrode thickness, which can be understood as: the entire contact surface 11 is parallel to the surface in terms of electrode thickness; or, a portion of the contact surface 11 is parallel to the surface in terms of electrode thickness, and another portion intersects with the surface in terms of electrode thickness. For example, when the electrode is in a Z-shaped stacked form, the entire contact surface 11 is parallel to the surface in terms of electrode thickness; when the electrode is in a wound stacked form, a portion of the contact surface 11 is parallel to the surface in terms of electrode thickness.

[0064] It is understandable that the direction of expansion of battery cell 1 is the thickness direction of the electrode sheet. By applying pressure to battery cell 1 along the thickness direction of the electrode sheet, the expansion force of battery cell 1 can be effectively controlled.

[0065] By attaching the control element 2 to the contact surface 11, with at least a portion of the contact surface 11 parallel to the plane containing the electrode, the control element 2 can apply pressure to the battery cell 1 along the thickness direction of the electrode, thus more effectively adjusting the expansion force of the battery cell 1. This is beneficial for further improving the performance and safety of the battery pack and extending its service life.

[0066] Optionally, all parts of the contact surface 11 are in contact with the control element 2.

[0067] For example, such as Figure 1 and Figure 2 As shown, the control component 2 is arranged on the front and rear sides of the battery cell 1, and each part of the front side of the battery cell 1 is in contact with the control cavity 21 located on the front side of the battery cell 1.

[0068] By ensuring that all parts of the contact surface 11 are in contact with the control element 2, the contact area between the control element 2 and the battery cell 1 can be increased. This not only increases the heat exchange efficiency between the control element 2 and the battery cell 1, but also increases the pressure applied by the control element 2 to the battery cell 1, facilitating the adjustment of the expansion force of the battery cell 1. Therefore, this is beneficial for further improving the performance and safety of the battery pack and extending its service life.

[0069] Optionally, control component 2 is a metal component.

[0070] For example, the control component 2 is made of aluminum, so that when the pressure in the control cavity 21 decreases, the control component 2 can remain intact and will not collapse, and when the pressure in the control cavity 21 increases, the control component 2 will not break.

[0071] Optionally, such as Figure 3 As shown, the control cavity 21 includes a plurality of first walls 211, and two adjacent first walls 211 intersect.

[0072] For example, such as Figure 3 As shown, the four first walls 211 are connected end to end in sequence, and the projection of the four first walls 211 forms a parallelogram, so that every two adjacent first walls 211 intersect.

[0073] It is understandable that when the pressure in the control cavity 21 changes, the force exerted by the control medium on the first wall 211 within the control cavity 21 will change, causing a slight deformation of the control cavity 21, which in turn causes a change in the size of the control component 2. Furthermore, the slight deformation of the control cavity 21 will also cause a slight deformation of the heat exchange cavity 22, resulting in a change in the size of the control component 2. This, in turn, causes a change in the size of the battery cell 1, thereby regulating the expansion force of the battery cell 1.

[0074] By setting two adjacent first walls 211 to intersect, the control component 2 is easy to deform when the pressure in the control cavity 21 changes, so as to better adjust the expansion force of the battery cell 1.

[0075] Optionally, the included angle between at least two adjacent first wall surfaces 211 is an acute angle.

[0076] For example, such as Figure 3 As shown, the four first walls 211 are connected end to end to form four included angles, two of which are acute angles and the other two are obtuse angles.

[0077] By setting the included angle between at least two adjacent first walls 211 to an acute angle, the control element 2 is more likely to deform when the pressure in the control cavity 21 changes, so as to better adjust the expansion force of the battery cell 1.

[0078] Optionally, such as Figure 3 As shown, the heat exchange cavity 22 includes a plurality of second walls 221, and two adjacent second walls 221 intersect.

[0079] For example, such as Figure 3 As shown, the four second walls 221 are connected end to end in sequence, and the projection of the four second walls 221 forms a parallelogram, so that every two adjacent second walls 221 intersect.

[0080] Understandably, when the pressure in the heat exchange chamber 22 changes, the force exerted by the control medium within the heat exchange chamber 22 on the second wall 221 changes, causing a slight deformation of the heat exchange chamber 22, which in turn causes a change in the size of the control component 2. This, in turn, causes a change in the size of the battery cell 1, thereby regulating the expansion force of the battery cell 1.

[0081] By setting two adjacent second walls 221 to intersect, the heat exchange cavity 22 is easy to deform when the pressure changes, so as to better adjust the expansion force of the battery cell 1.

[0082] Optionally, the included angle between at least two adjacent second wall surfaces 221 is an acute angle.

[0083] For example, such as Figure 3 As shown, the four second walls 221 are connected end to end to form four included angles, two of which are acute angles and the other two are obtuse angles.

[0084] By setting the included angle between at least two adjacent second walls 221 to an acute angle, the heat exchange chamber 22 is more likely to deform when the pressure changes, so as to better adjust the expansion force of the battery cell 1.

[0085] Optionally, such as Figure 3 As shown, there are multiple control chambers 21, and heat exchange chambers 22 are located between two adjacent control chambers 21.

[0086] For example, the control chamber 21 and the heat exchange chamber 22 are arranged alternately.

[0087] By setting multiple control chambers 21 and placing heat exchange chambers 22 between adjacent control chambers 21, the arrangement of control chambers 21 and heat exchange chambers 22 on the control component 2 is more uniform. On the one hand, this results in a more uniform pressure distribution applied to the battery cell 1 by the control component 2, avoiding excessive local stress on the battery cell 1. On the other hand, it helps improve the heat exchange uniformity between the control component 2 and the battery cell 1, thereby improving the temperature uniformity of the battery pack. This, in turn, helps to further improve the performance of the battery pack and extend its service life.

[0088] Optionally, such as Figure 3 As shown, there are multiple heat exchange chambers 22, and the control chamber 21 is located between two adjacent heat exchange chambers 22.

[0089] For example, the heat exchange chamber 22 and the control chamber 21 are arranged alternately at intervals.

[0090] By setting multiple heat exchange chambers 22 and placing the control chamber 21 between two adjacent heat exchange chambers 22, the arrangement of the heat exchange chambers 22 and control chamber 21 on the control component 2 is more uniform. On the one hand, this improves the heat exchange uniformity between the control component 2 and the battery cell 1, thereby improving the temperature uniformity of the battery pack. On the other hand, it makes the pressure distribution of the control component 2 on the battery cell 1 more uniform, avoiding excessive local stress on the battery cell 1. Therefore, this is beneficial for further improving the performance of the battery pack and extending its service life.

[0091] Optionally, the control chamber 21 and the heat exchange chamber 22 are arranged alternately.

[0092] The alternating arrangement of the control chamber 21 and the heat exchange chamber 22 can further improve the temperature uniformity of the battery pack and the uniformity of the pressure distribution applied by the control component 2 to the battery cell 1, which is conducive to further improving the performance of the battery pack and extending its service life.

[0093] Optionally, such as Figures 1 to 3 As shown, the control element 2 is disposed on at least one side of the battery cell 1 in a first direction, and the heat exchange chamber 22 and the control chamber 21 are alternately arranged along a second direction. The second direction is perpendicular to the first direction.

[0094] For example, the first direction is consistent with the front-back direction, and the second direction is consistent with the left-right direction. The control element 2 is disposed on at least one side of the battery cell 1 in the front-back direction, and the heat exchange chamber 22 and the control chamber 21 are arranged alternately in the left-right direction.

[0095] By arranging the control element 2 on at least one side of the battery cell 1 in the first direction, and the heat exchange chamber 22 and the control chamber 21 alternately arranged in the second direction, both the heat exchange chamber 22 and the control chamber 21 can be arranged close to the battery cell 1. This not only helps to improve the heat exchange efficiency between the control element 2 and the battery cell 1, but also makes it convenient to apply pressure to the battery cell 1 using the control element 2, which is beneficial to further improve the performance of the battery pack and extend the service life of the battery pack.

[0096] Optionally, such as Figure 1 and Figure 2 As shown, the control unit 2 is disposed on opposite sides of the battery cell 1 in the first direction.

[0097] For example, such as Figure 1 and Figure 2 As shown, control components 2 are provided on both the front and rear sides of the battery cell 1. These control components 2 can apply pressure to the battery cell 1 and achieve cooling or heating. This further improves the performance and safety of the battery pack and extends its service life.

[0098] Optionally, the battery cell 1 has a first cross-section cut by a plane perpendicular to a third direction, and the control member 2 has a second cross-section cut by a plane perpendicular to a third direction. The third direction is perpendicular to the first and second directions. The area of ​​the first cross-section is S1, and the area of ​​the second cross-section is S2, where S1 > 6 * S2.

[0099] Experimental tests on the battery pack showed that when S1>6*S2, the volumetric energy density of the battery pack is relatively high, and the heat exchange effect between the control component 2 and the battery cell 1 can be guaranteed; while when S1<6*S2, the volumetric energy density of the battery pack is relatively low, and the heat exchange effect between the control component 2 and the battery cell 1 is not significantly increased.

[0100] For example, when S1 = S2 * 7, the highest temperature at the end of fast charging of the battery pack is 43℃, and the volumetric energy density of the battery pack is 260Wh / L after the temperature rises by 7℃; when S1 = S2 * 5, the highest temperature at the end of fast charging of the battery pack is 42℃, and the volumetric energy density of the battery pack is 220Wh / L after the temperature rises by 7℃.

[0101] Therefore, by setting S1 and S2 to S1>6*S2, the volumetric energy density of the battery pack can be increased while ensuring the performance of the battery pack.

[0102] like Figure 1 and Figure 2 As shown, the battery pack includes an end plate 4, with battery cells 1 and control components 2 sandwiched between them. The end plate 4 is a rigid structural component and is structurally stable. Battery cells 1 and control components 2 have a certain degree of deformability.

[0103] For example, there are two end plates 4, namely the first end plate 41 and the second end plate 42. The first end plate 41 is located in front of the second end plate 42. Multiple battery cells 1 and control components 2 are sandwiched between the first end plate 41 and the second end plate 42 in the front-back direction, and the battery cells 1 and control components 2 are arranged alternately in the front-back direction.

[0104] like Figure 2 As shown, let L0 be the distance between the first end plate 41 and the second end plate 42, L1 be the thickness of the control component 2 in the front-to-back direction, a be the number of control components 2, L2 be the thickness of the battery cell 1 in the front-to-back direction, and b be the number of battery cells 1. Then L0 = a*L1 + b*L2. For example, as... Figure 2 As shown, the number of control components 2 is 4, the number of battery cells 1 is 3, and L0 = 4*L1 + 3*L2.

[0105] When L0, a, and b are fixed values, L2 can be adjusted by adjusting L1. Furthermore, when L2 is a fixed value, the dimensions of the control cavity 21 and heat exchange cavity 22 in the front-to-back direction are negatively correlated with the thickness of the outer shell of the control component 2. That is, the thinner the outer shell of the control component 2, the larger the dimensions of the control cavity 21 and heat exchange cavity 22 in the front-to-back direction, and the larger the volume of the control cavity 21 and heat exchange cavity 22; conversely, the thicker the outer shell of the control component 2, the smaller the dimensions of the control cavity 21 and heat exchange cavity 22 in the front-to-back direction, and the smaller the volume of the control cavity 21 and heat exchange cavity 22.

[0106] Optionally, the heat exchange cavity 22 has a third cross section cut by a section perpendicular to the third direction, the area of ​​the third cross section being S3, wherein S2 < 2*S3 and S2 > 1.05*S3.

[0107] Experimental testing of the battery pack revealed that when the proportion of the heat exchange cavity 22 is too large, the outer shell of the control component 2 is too thin, resulting in poor structural stability of the control component 2; when the proportion of the heat exchange cavity 22 is too small, the outer shell of the control component 2 is too thick, making the control component 2 difficult to deform and prone to losing its function of regulating the expansion force of the battery cell 1.

[0108] For example, when S2 = S3 * 2.5, the highest temperature at the end of fast charging of the battery pack is 51℃, an increase of 12℃, and the volumetric energy density of the battery pack is 260Wh / L. The temperature at the end of fast charging is too high, making it impossible to effectively cool and dissipate heat from the battery cell 1. Furthermore, the deformation of the control component 2 is too small, making it impossible to effectively adjust the thickness of the battery cell 1. When S2 = S3 * 1.5, the highest temperature at the end of fast charging of the battery pack is 43℃, an increase of 7℃, and the volumetric energy density of the battery pack is 260Wh / L. When S2 = S3 * 1.01, the highest temperature at the end of fast charging of the battery pack is 43℃, an increase of 7℃, and the control component 2 experiences a heat exchange medium leakage problem.

[0109] Therefore, by setting S2 and S3 to S2<2*S3 and S2>1.05*S3, the structural stability of the control component 2 can be guaranteed while making the control component 2 easier to deform, so as to better adjust the expansion force of the battery cell 1.

[0110] Optionally, the control cavity 21 has a fourth cross section cut by a section perpendicular to the third direction, the area of ​​the fourth cross section being S4, where S3 < 10 * S4 and S3 > 2 * S4.

[0111] Experimental testing of the battery pack revealed that when the proportion of the control cavity 21 is too large, the volumetric energy density of the battery pack is too low; when the proportion of the control cavity 21 is too small, the outer shell of the control component 2 is too thick, the control component 2 is not easily deformed, and it is easy to lose its function of regulating the expansion force of the battery cell 1.

[0112] For example, when S4*12 = S3, the expansion force of battery cell 1 cannot be adjusted to an ideal state; when S4*4 = S3, the highest temperature at the end of fast charging of the battery pack is 43℃, the temperature rises by 7℃, and the volumetric energy density of the battery pack is 260Wh / L; when S4*1.5 = S3, the highest temperature at the end of fast charging of the battery pack is 46℃, the temperature rises by 8℃, and the volumetric energy density of the battery pack is 240Wh / L. The battery pack has a high temperature and low energy density, resulting in no positive benefit.

[0113] Therefore, by setting S3 and S4 to S3<10*S4 and S3>2*S4, it is possible to ensure that the energy density of the battery pack is high while ensuring that the proportion of the control cavity 21 is not too small, so as to better achieve the adjustment of the expansion force of the battery cell 1.

[0114] Optionally, S2 < 20 * S4 and S2 > 3 * S4.

[0115] Experimental testing of the battery pack revealed that when the proportion of the control cavity 21 is too large, the volumetric energy density of the battery pack is too low; when the proportion of the control cavity 21 is too small, the outer shell of the control component 2 is too thick, the control component 2 is not easily deformed, and it is easy to lose its function of regulating the expansion force of the battery cell 1.

[0116] For example, when S4*25 = S2, the expansion force of battery cell 1 cannot be adjusted to an ideal state; when S4*10 = S2, the highest temperature at the end of fast charging of the battery pack is 43℃, the temperature rises by 7℃, and the volumetric energy density of the battery pack is 260Wh / L; when S4*2 = S2, the highest temperature at the end of fast charging of the battery pack is 46℃, the temperature rises by 8℃, and the volumetric energy density of the battery pack is 240Wh / L. The battery pack has a high temperature and low energy density, resulting in no positive benefit.

[0117] Therefore, by setting S2 and S4 to S2<20*S4 and S2>3*S4, it is possible to ensure that the energy density of the battery pack is high while ensuring that the proportion of the control cavity 21 is not too small, so as to better achieve the adjustment of the expansion force of the battery cell 1.

[0118] The battery pack control method of this disclosure includes: obtaining the state of oxygen (SOH) and / or state of charge (SOC) of the battery pack, and controlling the system 3 to adjust the pressure of the control chamber 21 so that the pressure of at least one of the battery cell 1, the heat exchange chamber 22 and the control chamber 21 is the corresponding target pressure.

[0119] State of Health (SOH) refers to the battery's health status, that is, the degree of performance degradation of the battery during use. It reflects the percentage of the battery's remaining capacity relative to its initial design capacity. For example, if a battery has an SOH of 80%, it means that the battery's usable capacity is equivalent to 80% of its initial design capacity. The SOH value typically decreases gradually with battery use, charge-discharge cycles, and age. By monitoring the SOH of a battery pack, the lifespan and performance of the battery pack can be assessed, and it can be determined when the battery pack needs to be replaced.

[0120] SOC (State of Charge) refers to the battery's state of charge, which is the ratio between the battery's current stored charge level and its maximum charging capacity. SOC reflects how much usable electrical energy remains in the battery. For example, if a battery's SOC is 50%, it means that the battery currently stores half of its maximum charging capacity. The SOC value is typically estimated by monitoring the battery pack's voltage, current, and charging / discharging behavior.

[0121] Understandably, the target pressure corresponding to battery cell 1 differs depending on the state of equilibrium (SOH) of the battery pack, and the target pressure corresponding to battery cell 1 also differs depending on the state of charge (SOC) of the battery pack. The target pressure corresponding to battery cell 1 can be understood as the pressure of battery cell 1 when its performance is at its optimal state. Since the pressures of battery cell 1, heat exchange chamber 22, and control chamber 21 are interconnected, when adjusting the pressure of control chamber 21 to improve the cycle performance of battery cell 1, it is also necessary to consider the pressure of control chamber 21 itself and the pressure of heat exchange chamber 22 to ensure the overall battery pack is in good condition.

[0122] State of Health (SOH) can be obtained through methods such as calculation by the battery management system, calculation by the DC internal resistance of parallel cell units, and calculation by accumulated capacity. State of Charge (SOC) can be obtained through methods such as current integration, open-circuit voltage method, fusion algorithm, and SOC estimation method based on battery performance.

[0123] The target pressure of control chamber 21 can be understood as the pressure of control chamber 21 when the battery pack is in its optimal operating state; the target pressure of heat exchange chamber 22 can be understood as the pressure of heat exchange chamber 22 when the battery pack is in its optimal operating state. The optimal operating state of the battery pack includes the comprehensive performance of the battery pack, such as energy density, cycle performance, safety performance, and service life.

[0124] The pressure of the control chamber 21 can be obtained through a pressure detection device, such as a pressure regulating valve or pressure pump connected to the control chamber 21.

[0125] The pressure of the heat exchange chamber 22 can be obtained by detecting the flow rate of the heat exchange medium and calculating the pressure of the heat exchange chamber 22 based on the flow rate of the heat exchange medium and relevant parameters of the heat exchange chamber 22. The flow rate of the heat exchange medium can be obtained from the battery thermal management system of the battery pack.

[0126] The pressure of battery cell 1 can be obtained by the following method: by detecting the expansion force of battery cell 1, the pressure of battery cell 1 is calculated based on the expansion force. The method for detecting the expansion force of battery cell 1 is existing technology and will not be described in detail here.

[0127] The battery pack control method of this disclosure, by obtaining the SOH and / or SOC, controls the system 3 to adjust the pressure of the control chamber 21 so that the pressure of at least one of the battery cell 1, the heat exchange chamber 22 and the control chamber 21 is the corresponding target pressure, which can make the battery pack as a whole in the best working state, which is beneficial to improving the performance of the battery pack and extending the service life of the cells.

[0128] Optionally, when the SOH is greater than or equal to 95%, the control system 3 adjusts the pressure of the control chamber 21 so that the pressure of the battery cell 1 is the corresponding target pressure.

[0129] The control system 3 may include a battery thermal management system, which regulates the flow rate of the heat exchange medium within the heat exchange chamber 22. This battery thermal management system is prior art and will not be described in detail here. The heat exchange chamber 22 can be connected to the battery thermal management system via piping.

[0130] By adjusting the pressure of battery cell 1 to the corresponding target pressure, the expansion force of battery cell 1 is optimized, thereby improving the performance of battery cell 1 and extending the life of the cell, and thus improving the performance of the battery pack and extending the life of the battery pack.

[0131] Let P0 be the target pressure, P1 be the pressure of battery cell 1, P2 be the pressure of heat exchange chamber 22, and P3 be the pressure of control chamber 21. The target pressure P0 varies depending on the state of equilibrium (SOH), and P0 represents the inherent property of battery cell 1. When SOH is greater than 95%, P1 ≤ P2, P3 > P2 > P1, and control system 3 adjusts the pressure of control chamber 21 to make P1 = P0.

[0132] In addition, when the SOH is greater than or equal to 95%, the expansion of the battery cell 1 is small and the heat generation is the highest. The battery cell 1 needs to be cooled quickly. The flow rate of the heat exchange medium in the heat exchange chamber 22 needs to be adjusted to the maximum flow rate to increase the cooling effect of the control unit 2 on the battery cell 1.

[0133] Optionally, when SOH is less than 60%, the control system 3 adjusts the control chamber 21 to an open state or adjusts the pressure of the control chamber 21 to zero. In this case, when the control chamber 21 is in the open state, the corresponding pressure of the control chamber 21 is the target pressure of the control chamber 21, or the target pressure of the control chamber 21 is zero.

[0134] It can be understood that when SOH is less than 60%, the battery pack enters the end-of-life stage, the expansion of the battery cell 1 is extremely large, and the space redundancy in the battery pack is almost exhausted. At this time, the control chamber 21 may no longer be sealed, or the pressure of the control chamber 21 is set to zero, and the pressure of the heat exchange chamber 22 and the pressure of the battery cell 1 are no longer assessed. That is, when SOH is less than 60%, the control system 3 adjusts the control chamber 21 so that P3=0, and the relationship between P2 and P1 is no longer assessed.

[0135] By adjusting the control chamber 21 to an open state or adjusting the pressure of the control chamber 21 to zero, the size of the control member 2 can be reduced to the maximum extent, thereby providing more space for the expansion of the battery cell 1, reducing the risk of rupture or short circuit of the battery cell 1, improving the safety of the battery cell 1, and thus improving the safety of the battery pack.

[0136] Optionally, when SOH is less than 95% and greater than or equal to 60%, and the pressure of the battery cell 1 is greater than the pressure of the heat exchange chamber 22, the control system 3 adjusts the pressure of the control chamber 21 so that the pressure of the control chamber 21 is less than the pressure of the heat exchange chamber 22.

[0137] It can be understood that when SOH is less than 95% and greater than or equal to 60%, the redundant space in the battery pack is small. At this time, the pressure of the battery cell 1, the pressure of the control chamber 21 and the pressure of the heat exchange chamber 22 are dynamically correlated. When the pressure of the battery cell 1 is greater than the pressure of the heat exchange chamber 22, the pressure of the control chamber 21 is preferentially reduced, so that the pressure of the control chamber 21 is less than the pressure of the heat exchange chamber 22, so that the heat exchange chamber 22 remains stable, so as to ensure the heat exchange effect between the control member 2 and the battery cell 1. That is, when SOH is less than 95% and greater than 60%, P3, P2 and P1 are dynamically correlated. When P1 is greater than P2, P3 is preferentially reduced, so that P3 < P2, the control chamber 21 is compressed, and the heat exchange chamber 22 is kept stable.

[0138] Therefore, when SOH is less than 95% and greater than or equal to 60%, and the pressure of the battery cell 1 is greater than the pressure of the heat exchange chamber 22, making the pressure of the control chamber 21 less than the pressure of the heat exchange chamber 22 can ensure the heat exchange effect between the control member 2 and the battery cell 1 and improve the overall performance of the battery pack.

[0139] In other embodiments, when the SOH is less than 95% and greater than or equal to 60%, and the pressure of the battery cell 1 is less than the pressure of the heat exchange chamber 22, the control system 3 adjusts the pressure of the control chamber 21 so that the pressure of the battery cell 1 is the corresponding target pressure.

[0140] Understandably, when the State of Hypothesis (SOH) is less than 95% but greater than or equal to 60%, the redundancy space within the battery pack is relatively small. In this case, the pressure of battery cell 1, the pressure of control chamber 21, and the pressure of heat exchange chamber 22 are dynamically correlated. When the pressure of battery cell 1 is less than the pressure of heat exchange chamber 22, the pressure of control chamber 21 is preferentially increased to bring the pressure of battery cell 1 to the corresponding target pressure, thus ensuring the performance and lifespan of battery cell 1. That is, when the SOH is less than 95% but greater than 60%, P3, P2, and P1 are dynamically correlated; when P1 is less than P2, P3 is increased to make P1 = P0.

[0141] Therefore, when SOH is less than 95% and greater than or equal to 60%, and the pressure of battery cell 1 is less than the pressure of heat exchange chamber 22, adjusting the pressure of control chamber 21 to make the pressure of battery cell 1 the corresponding target pressure is beneficial to improving the performance of battery pack and extending the service life of battery pack.

[0142] It is understandable that the pressure of battery cell 1 is also affected by the SOC of the battery pack, and the SOC is directly proportional to the pressure of battery cell 1. That is, the larger the SOC, the greater the pressure of battery cell 1, and the smaller the SOC, the smaller the pressure of battery cell 1.

[0143] Optionally, when the SOC is greater than or equal to a preset value, the control system 3 adjusts the pressure of the control chamber 21 to reduce it, so that the pressure of the battery cell 1 is the corresponding target pressure. That is, when the SOC rises to or above the preset value, P3 is adjusted to reduce it, providing expansion space for the battery cell 1, so that P1 = P0.

[0144] This preset value can be set as needed. The corresponding target pressure will vary depending on the state of pressure (SOC).

[0145] When the SOC is greater than or equal to the preset value, the corresponding target pressure is relatively large. Adjusting the pressure of the control chamber 21 so that the pressure of the battery cell 1 is the corresponding target pressure is beneficial to improving the performance of the battery pack and extending the service life of the battery pack.

[0146] Optionally, when the SOC is less than a preset value, the control system 3 adjusts the pressure of the control chamber 21 to increase so that the pressure of the battery cell 1 is the corresponding target pressure. That is, when the SOC drops below the preset value, P3 is adjusted to increase P3, thereby making P1 = P0.

[0147] When the SOC is less than the preset value, the corresponding target pressure is smaller. Adjusting the pressure of the control chamber 21 so that the pressure of the battery cell 1 is the corresponding target pressure is beneficial to improving the performance of the battery pack and extending the service life of the battery pack.

[0148] The control system 3 can intelligently control the pressure of the control cavity 21 based on various parameters of the battery pack, thereby achieving intelligent control of the battery pack. That is, it intelligently controls the pressure of the control cavity 21, thereby intelligently controlling the interaction force between the control component 2 and the battery cell 1, and thus intelligently controlling the thickness of the battery cell 1 and the thickness of the control component 2.

[0149] The following example uses a battery cell 1 within the battery pack, where the cross-sectional area S1 is 4200 mm². 2 The cross-sectional area S2 of control component 2 is 450 mm. 2 The cross-sectional area S3 of the heat exchange cavity 22 is 350 mm. 2 The cross-sectional area S4 of the control cavity 21 is 70 mm. 2 For example.

[0150] When SOH = 100%;

[0151] When SOC = 0, P0 = 18 kPa;

[0152] At this point, adjust P3 so that P1 = 18 kPa, P2 = 9 kPa, and P3 = 28 kPa;

[0153] When SOC = 50%, P0 = 20 kPa;

[0154] At this point, adjust P3 so that P1 = 20 kPa, P2 = 9 kPa, and P3 = 26 kPa;

[0155] When SOC = 100%, P0 = 22 kPa;

[0156] At this point, adjust P3 so that P1 = 22 kPa, P2 = 9 kPa, and P3 = 24 kPa.

[0157] When SOH = 90%;

[0158] When SOC = 0, P0 = 20 kPa;

[0159] At this point, adjust P3 so that P1 = 20 kPa, P2 = 10 kPa, and P3 = 26 kPa;

[0160] When SOC = 50%, P0 = 20 kPa;

[0161] At this point, adjust P3 so that P1 = 20 kPa, P2 = 10 kPa, and P3 = 24 kPa;

[0162] When SOC = 100%, P0 = 22 kPa;

[0163] At this point, adjust P3 so that P1 = 22 kPa, P2 = 11 kPa, and P3 = 23 kPa.

[0164] When SOH = 70%;

[0165] When SOC = 0, P0 = 22 kPa;

[0166] At this point, adjust P3 so that P1 = 22 kPa, P2 = 9 kPa, and P3 = 15 kPa;

[0167] When SOC = 50%, P0 = 23 kPa;

[0168] At this point, adjust P3 so that P1 = 23 kPa, P2 = 10 kPa, and P3 = 6 kPa;

[0169] When SOC = 100%, P0 = 24 kPa;

[0170] At this point, adjust P3 so that P1 = 26 kPa, P2 = 13 kPa, and P3 = 0.

[0171] In summary, within a wide range, P1 can be adjusted to be as close to P0 as possible while adjusting P3, thereby improving the performance of the battery pack and extending its service life.

[0172] The battery pack of this embodiment adjusts the pressure of the battery cell 1 by adjusting the pressure of the control chamber 21 of the control component 2, thereby adjusting the expansion force of the battery cell 1, giving the battery pack the following advantages:

[0173] Improved battery pack safety: By reducing the expansion of individual battery cells 1, the risk of individual battery cells 1 rupture or short circuit can be reduced, improving the safety of individual battery cells 1 in use, and thus improving the safety of the battery pack.

[0174] Extended battery pack lifespan: By reducing the expansion of individual battery cells 1, fatigue and degradation of the internal materials of individual battery cells 1 can be slowed down, thus extending the battery pack lifespan.

[0175] Maintaining stable battery pack performance: By reducing the expansion of individual battery cells 1, it helps to maintain the integrity of the internal structure of individual battery cells 1, maintain the discharge capacity and power output of individual battery cells 1, and ensure the stability of battery pack performance.

[0176] Improving battery pack consistency: By controlling the expansion force of individual battery cells 1, it is helpful to maintain the consistency of each individual battery cell 1 in the battery pack, which is crucial for the overall performance and reliability of the battery pack.

[0177] The vehicle in this disclosure includes the battery pack described in any of the above embodiments. The vehicle can be an electric vehicle.

[0178] The battery pack of this disclosure can also be used in other devices that require power, such as power tools.

[0179] Although embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the scope of protection of the present disclosure.

Claims

1. A battery pack, characterized in that, include: Box; The battery cell and the control component are both housed within the housing. The control component has a control cavity and abuts against the battery cell to apply pressure to the battery cell. A control system is connected to the control cavity to adjust the pressure of the control cavity.

2. The battery pack according to claim 1, characterized in that, The control unit is also provided with a heat exchange chamber for the flow of heat exchange medium to exchange heat with the battery cells.

3. The battery pack according to claim 1 or 2, characterized in that, The control component is attached to the battery cell.

4. The battery pack according to claim 3, characterized in that, The battery cell includes multiple outer surfaces, at least one of which is a contact surface; The battery cell includes an electrode sheet, at least a portion of the contact surface is parallel to the thickness direction of the electrode sheet, and the control element is attached to the contact surface.

5. The battery pack according to claim 2, characterized in that, The control cavity includes multiple first walls, with adjacent first walls intersecting; and / or The heat exchange cavity includes multiple second walls, with adjacent second walls intersecting.

6. The battery pack according to claim 2, characterized in that, The control chamber and the heat exchange chamber are arranged alternately.

7. The battery pack according to claim 2, characterized in that, The control element is disposed on at least one side of the battery cell in a first direction, and the heat exchange cavity and the control cavity are alternately arranged along a second direction, which is perpendicular to the first direction.

8. The battery pack according to claim 7, characterized in that, The control components are disposed on opposite sides of the battery cell in the first direction.

9. The battery pack according to claim 7, characterized in that, The battery cell has a first cross-section cut by a plane perpendicular to a third direction, and the control element has a second cross-section cut by a cross-section perpendicular to a third direction, wherein the third direction is perpendicular to both the first and second directions. The area of ​​the first cross-section is S1, and the area of ​​the second cross-section is S2, where S1 > 6 * S2.

10. The battery pack according to claim 7, characterized in that, The control element has a second cross-section cut by a section perpendicular to a third direction, and the heat exchange cavity has a third cross-section cut by a section perpendicular to a third direction, which is perpendicular to the first direction and the second direction. The area of ​​the second cross section is S2, and the area of ​​the third cross section is S3, wherein S2 < 2 * S3 and S2 > 1.05 * S3.

11. The battery pack according to claim 7, characterized in that, The heat exchange cavity has a third cross section cut by a section perpendicular to a third direction, and the control cavity has a fourth cross section cut by a section perpendicular to a third direction, which is perpendicular to the first direction and the second direction. The area of ​​the third cross section is S3, and the area of ​​the fourth cross section is S4, wherein S3 < 10 * S4 and S3 > 2 * S4.

12. The battery pack according to claim 7, characterized in that, The control element has a second cross section cut by a section perpendicular to a third direction, and the control cavity has a fourth cross section cut by a section perpendicular to a third direction, the third direction being perpendicular to the first direction and the second direction; The area of ​​the second cross section is S2, and the area of ​​the fourth cross section is S4, wherein S2 < 20 * S4 and S2 > 3 * S4.

13. The battery pack according to claim 1 or 2, characterized in that, The control system includes a medium supply device and a pressure regulating device. The medium supply device is connected to the control cavity to provide a control medium to the control cavity. The pressure regulating device is connected to the medium supply device to regulate the pressure of the control medium flowing from the medium supply device into the control cavity.

14. The battery pack according to claim 13, characterized in that, The medium supply device is an air compressor, and the pressure regulating device is a pressure regulating valve; or The medium supply device is a pressure storage tank, and the pressure regulating device is a pressure pump.

15. A method for controlling a battery pack, characterized in that, The battery pack is the battery pack according to any one of claims 2, 5-12, and the control method for the battery pack includes: The control system obtains the state of equilibrium (SOH) and / or state of charge (SOC) of the battery pack, and adjusts the pressure of the control chamber to make the pressure of at least one of the battery cells, the heat exchange chamber, and the control chamber the corresponding target pressure.

16. The battery pack control method according to claim 15, characterized in that, When the SOH is greater than or equal to 95% The control system adjusts the pressure of the control chamber to make the pressure of the battery cell the corresponding target pressure.

17. The battery pack control method according to claim 15, characterized in that, When the SOH is less than 60%, the control system adjusts the control chamber to an open state or the pressure of the control chamber to zero.

18. The battery pack control method according to claim 15, characterized in that, When the SOH is less than 95% and greater than or equal to 60%, and the pressure of the battery cell is greater than the pressure of the heat exchange chamber, the control system adjusts the pressure of the control chamber to make the pressure of the control chamber less than the pressure of the heat exchange chamber. When the SOH is less than 95% and greater than or equal to 60%, and the pressure of the battery cell is less than the pressure of the heat exchange chamber, the control system adjusts the pressure of the control chamber to make the pressure of the battery cell the corresponding target pressure.

19. The battery pack control method according to claim 15, characterized in that, When the SOC is greater than or equal to a preset value, the control system adjusts the pressure of the control cavity to reduce the pressure of the battery cell to the corresponding target pressure. When the SOC is less than a preset value, the control system adjusts the pressure of the control cavity to increase so that the pressure of the battery cell is the corresponding target pressure.

20. A vehicle, characterized in that, The battery pack includes any one of claims 1-14.

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