Battery pack and battery system

Abstract

The invention relates to the technical field of batteries, and discloses a battery pack and a battery system. The battery pack comprises a shell, a first battery pack and a second battery pack. The first battery pack comprises a plurality of first battery monomers which are connected in series, and a first gap exists between every four adjacent first battery monomers or between every two adjacent first battery monomers and the shell; the second battery pack comprises a plurality of second single batteries which are connected in series, the diameter of each second single battery is smaller than that of each first single battery, and each second single battery is arranged in one first gap. According to the battery pack provided by the invention, the two battery packs with different diameters are arranged in the shell, so that the space in the shell can be fully utilized, the gap between the adjacent single batteries is further reduced, the integration level is improved, and the overall energy density is improved. Two different battery packs are integrated in one battery pack, the first battery pack and the second battery pack can be flexibly controlled, switching of different application scenes and function implementation are achieved, and the function of the battery pack is widened.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a battery pack and a battery system. Background Art

[0002] Lithium-ion batteries are widely used due to their advantages such as good rate performance, high safety, large capacity, long cycle life, and green environmental protection. Especially in the field of power and energy storage, highly integrated lithium-ion battery packs have received widespread attention. Cylindrical batteries are widely used in energy storage and power battery fields due to their high energy density, flexible arrangement, and stable safety performance.

[0003] However, the current single cell capacity of cylindrical batteries is less restricted by process conditions. The cylindrical battery cells are affected by their shape, and the overall energy density after integration is low. Summary of the invention

[0004] In view of this, the present invention provides a battery pack and a battery system to solve the problem of low overall energy density after cylindrical battery cells are integrated.

[0005] In a first aspect, the present invention provides a battery pack, comprising a housing and a first battery group and a second battery group disposed in the housing. The first battery group comprises a plurality of first battery cells connected in series, the plurality of first battery cells are closely arranged in a manner of parallel axes, and a first gap exists between four adjacent first battery cells, or between two adjacent first battery cells and the housing; the second battery group comprises a plurality of second battery cells connected in series, the diameter of the second battery cells is smaller than the diameter of the first battery cells, and each second battery cell is disposed in a first gap.

[0006] Beneficial effects: The battery pack provided by the present invention has two battery packs arranged in the shell, the diameter of the second battery cell in the second battery pack is smaller than the diameter of the first battery cell, and the second battery cell is placed between adjacent first battery cells or between adjacent first battery cells and the shell. In this way, the space in the shell can be fully utilized, and the gap between adjacent battery cells is further reduced, thereby improving the integration and thus improving the overall energy density. Battery cells of different sizes are integrated in the same battery pack, and two battery packs can be used separately as needed, or the two battery packs can be used to power different modules at the same time to match different application requirements, which is more flexible.

[0007] In an optional implementation, the radius of the first battery cell is r1, the radius of the second battery cell is r2, and r2≤(√2-1)×r1.

[0008] In an optional embodiment, in the first battery pack, adjacent first battery cells are connected in series through palladium sheets, and the battery pack connection and signal acquisition can be achieved through an integrated busbar system. A first positive lead wire and a first negative lead wire are provided on the first end face of the first battery pack, and the first positive lead wire and the first negative lead wire are connected to the first switch position; in the second battery pack, adjacent second battery cells are connected in series through wires, and a second positive lead wire and a second negative lead wire are provided on the second end face of the second battery pack, and the second positive lead wire and the second negative lead wire are connected to the second switch position; the second end face and the first end face are arranged opposite to each other.

[0009] In an optional embodiment, a second gap exists between adjacent first battery cells and second battery cells; and a thermal runaway monitoring device is also included, which includes at least one pressure sensor arranged in the second gap, the pressure sensors are arranged at intervals along the axial direction of the first battery cell, and the pressure sensors abut against the outer peripheral walls of the three adjacent battery cells.

[0010] In an optional implementation, the pressure sensor is adhesively connected to the first battery cell and the second battery cell;

[0011] Or, it also includes a fixing frame, which includes a first hole position, a second hole position and at least one mounting groove, the first battery cell is arranged in the first hole position, the second battery cell is arranged in the second hole position, and each pressure sensor is arranged in a mounting groove.

[0012] In an optional embodiment, it also includes a first insulating sheet and a second insulating sheet, the first insulating sheet is arranged on the first end face, the second insulating sheet is arranged on the second end face, the first insulating sheet is provided with a plurality of first welding through holes and a plurality of second welding through holes, the second insulating sheet is provided with a plurality of second welding through holes, the first welding through holes are used to weld adjacent first battery cells in series, and the second welding through holes are used to weld adjacent second battery cells in series. Alternatively, the first insulating sheet is arranged on the first end face, the second insulating sheet is arranged on the second end face, the first insulating sheet is provided with a plurality of first welding through holes, the second insulating sheet is provided with a plurality of second welding through holes, the first welding through holes are used to weld adjacent first battery cells in series, and the second welding through holes are used to weld adjacent second battery cells in series. The specific welding arrangement is arranged according to the distribution of the tabs of the battery cell.

[0013] In a second aspect, the present invention further provides a battery system, comprising a BMS control module, an energy conversion module and a battery pack according to any one of the above technical solutions. The battery pack supplies power to the BMS control module and / or the energy conversion module.

[0014] Beneficial effects: The battery system provided by the present invention includes the battery pack in the above-mentioned embodiment. By integrating the dual battery groups into one battery system, the volume of the battery pack is utilized to the greatest extent, thereby improving the overall energy density of the battery system. Through flexible control, a set of products can meet different power demands, and can be switched for use when any battery group has abnormal pressure. This is more flexible and convenient, fully utilizes the battery group, has low cost, improves service life and system safety performance, and has high economic value.

[0015] In an optional embodiment, the first battery group and the second battery group in the battery pack are controlled in their working state by a BMS control module through communication; the first battery group of the battery pack is conductively connected to the energy conversion module, and the second battery group of the battery pack is conductively connected to the BMS control module; or the first battery group and the second battery group of the battery pack are conductively connected to the energy conversion module.

[0016] In an optional embodiment, it further includes a first compound switch and a second compound switch. In a first working state, the first battery group is conductively connected to the energy conversion module through the first compound switch, and the second battery group is conductively connected to the BMS control module through the second compound switch; in a second working state, the second battery group is conductively connected to the energy conversion module through the first compound switch, and the first battery group is conductively connected to the BMS control module through the second compound switch. The battery system is suitable for arbitrarily switching between the first working state and the second working state.

[0017] In an optional embodiment, it also includes a switching switch, one end of the switching switch is conductively connected to the energy conversion module, and the other end of the switching switch is provided with a first switch position and a second switch position. In the first switch position, the switching switch is conductively connected to the first battery pack, and in the second switch position, the switching switch is conductively connected to the second battery pack; a pressure sensor of the battery pack is communicatively connected to the BMS control module, and is used to transmit pressure data to the BMS control module. The BMS control module determines whether there is a pressure abnormality in the first battery pack or the second battery pack based on the pressure data. When there is a pressure abnormality in either the first battery pack or the second battery pack, the BMS control module can cut off the power supply circuit of the battery pack, or switch the switching switch to another switch position. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1Schematic diagram of the distribution structure of the first battery pack in the housing in an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of a first structure in which a dual battery pack is arranged in a housing in an embodiment of the present invention;

[0021] Figure 3 A second structural schematic diagram of a dual battery pack arranged in a housing according to an embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of a third structure in which a dual battery pack is arranged in a housing according to an embodiment of the present invention;

[0023] Figure 5 It is an enlarged view of a local structure in an embodiment of the present invention;

[0024] Figure 6 for Figure 5 A partial enlarged view of the middle A;

[0025] Figure 7 is a top view of a fixing frame in an embodiment of the present invention;

[0026] Figure 8 A schematic diagram of an installation structure of a pressure sensor in an embodiment of the present invention;

[0027] Fig. 9 A schematic diagram of a local structure of a battery pack according to an embodiment of the present invention;

[0028] Fig.10 A control diagram of a switch in a disconnected position in a first control scheme in a battery system according to an embodiment of the present invention;

[0029] Fig.11 A control diagram of a switch in a first switch position in a first control scheme in a battery system according to an embodiment of the present invention;

[0030] Fig.12 A control diagram of a switch in a second switch position in a first control scheme in a battery system according to an embodiment of the present invention;

[0031] Fig.13 A control diagram of a second control scheme in a battery system according to an embodiment of the present invention;

[0032] Fig.14 This is a control diagram of a battery system according to an embodiment of the present invention in which the first composite switch and the second composite switch are both in the disconnected position in the third control scheme;

[0033] Fig.15 This is a control diagram of the third control scheme in the battery system of an embodiment of the present invention in the first working state;

[0034] Fig.16 This is a control diagram of the third control scheme in the battery system of an embodiment of the present invention in the second working state.

[0035] Description of reference numerals:

[0036] 1. Shell; 2. First battery group; 21. First battery cell; 211. Positive pole; 22. First gap; 23. Palladium sheet; 24. First positive lead wire; 25. First negative lead wire; 3. Second battery group; 31. Second battery cell; 32. Second gap; 33. Wire; 34. Second positive lead wire; 35. Second negative lead wire; 41. First insulating sheet; 42. Second insulating sheet; 43. First welding through hole; 44. Second welding through hole; 45. Heat-insulating member; 46. Support member; 5. Pressure sensor; 6. Fixing bracket; 61. First hole position; 62. Second hole position; 63. Mounting groove. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0038] Combine the following Figures 1 to 16 Embodiments of the present invention are described.

[0039] According to an embodiment of the present invention, on the one hand, a battery pack is provided, including a housing 1 and a first battery group 2 and a second battery group 3 arranged in the housing 1. The first battery group 2 includes a plurality of first battery cells 21 connected in series, the plurality of first battery cells 21 are closely arranged in an axis-parallel manner, and a first gap 22 exists between four adjacent first battery cells 21, or between two adjacent first battery cells 21 and the housing 1, such as Figure 2 As shown; the second battery pack 3 includes a plurality of second battery cells 31 connected in series, the diameter of the second battery cell 31 is smaller than the diameter of the first battery cell 21, and each second battery cell 31 is respectively disposed in a first gap 22, such as Figures 2 to 4 shown.

[0040] The battery pack provided by the present invention has two battery groups arranged in the shell 1, the diameter of the second battery cell 31 in the second battery group 3 is smaller than the diameter of the first battery cell 21 in the first battery group 2, and the second battery cell 31 is placed between adjacent first battery cells 21 or between adjacent first battery cells 21 and the shell 1. In this way, the space in the shell 1 can be fully utilized, and the gap between adjacent battery cells is further reduced, thereby improving the integration and thus improving the overall energy density of the battery pack.

[0041] Different sized battery cells are integrated in the same battery pack to form a battery pack with dual battery packs. Two battery packs can be used separately as needed, or two battery packs can be used to power different modules at the same time to match different application requirements, which is more flexible. The specific control scheme will be described in detail in the second aspect of the present invention.

[0042] In some embodiments, the outer peripheral wall of the second battery cell 31 located between four adjacent first battery cells 21 is connected to the outer peripheral walls of the four first battery cells 21; the outer peripheral wall of the second battery cell 31 located between two adjacent first battery cells 21 and the shell 1 is connected to the two first battery cells 21 and the shell 1.

[0043] In some embodiments, the radius of the first battery cell 21 is r1, the radius of the second battery cell 31 is r2, and r2≤(√2-1)×r1.

[0044] Specifically, the second battery pack 3 is inserted into the first battery pack 2, and the arrangement includes the following: Figures 2 to 4 Here we use Figure 3 Take the arrangement shown as an example.

[0045] Since the second battery cell 31 is disposed in the first gap 22 , the radius r2 of the second battery cell 31 does not exceed (√2-1)×r1.

[0046] In some embodiments, in the first battery group 2, adjacent first battery cells 21 are connected in series via a palladium sheet 23, a first positive lead-out line 24 and a first negative lead-out line 25 are provided on a first end face of the first battery group 2, and the first positive lead-out line 24 and the first negative lead-out line 25 are connected to a first switch position; in the second battery group 3, adjacent second battery cells 31 are connected in series via a wire 33, a second positive lead-out line 34 and a second negative lead-out line 35 are provided on a second end face of the second battery group 3, and the second positive lead-out line 34 and the second negative lead-out line 35 are connected to a second switch position; the second end face and the first end face are arranged opposite to each other.

[0047] exist Fig. 9In the embodiment shown, the first end face is the upper end face, and the second end face is the lower end face. The total positive electrode (Battery1+) of the first battery group 2, i.e., the first positive electrode lead 24, and the total negative electrode (Battery1-) of the first battery group 2, i.e., the first negative electrode lead 25, are both arranged at the first end face; and the total positive electrode (Battery2+) of the second battery group 3, i.e., the second positive electrode lead 34, and the total negative electrode (Battery2-) of the second battery group 3, i.e., the second negative electrode lead 35, are both arranged at the second end, so that the wiring separation of the two battery groups is realized, which is beneficial to the line distribution.

[0048] In some embodiments, a first insulating sheet 41 and a second insulating sheet 42 are also included. The first insulating sheet 41 is arranged on the first end surface, and the second insulating sheet 42 is arranged on the second end surface. The first insulating sheet 41 is provided with a plurality of first welding through holes 43 and a plurality of second welding through holes 44, and the second insulating sheet 42 is provided with a plurality of second welding through holes 44. The first welding through holes 43 are used to weld adjacent first battery cells 21 in series, and the second welding through holes 44 are used to weld adjacent second battery cells 31 in series.

[0049] In other embodiments, the first insulating sheet 41 is provided on the first end surface, the second insulating sheet 42 is provided on the second end surface, the first insulating sheet 41 is provided with a plurality of first welding through holes 43, the second insulating sheet 42 is provided with a plurality of second welding through holes 44, the first welding through holes 43 are used to weld adjacent first battery cells 21 in series, and the second welding through holes 44 are used to weld adjacent second battery cells 31 in series. The specific welding arrangement is arranged according to the distribution of the tabs of the battery cell.

[0050] In this embodiment, since the diameter of the first battery cell 21 is relatively large, a positive electrode column 211 is provided at one end of the first battery cell 21, the shell 1 is negatively charged, and the shell 1 includes an end cover at one end, and the end cover and the positive electrode column are located at the same end. The first battery cells 21 are welded on the same side, and the positive electrode column 211 of one first battery cell 21 is welded to the end cover of another adjacent first battery cell 21 to achieve series connection. Since they are all welded on the same side, the total positive electrode and the total negative electrode of the first battery group 2 can be led out on the same side.

[0051] In this embodiment, since the diameter of the second battery cell 31 is relatively small, the second battery cell 31 adopts the method of having poles at both ends. Adjacent second battery cells 31 are placed upside down, that is, the positive pole 211 of one second battery cell 31 and the negative pole 211 of another adjacent second battery cell 31 are located on the same side. In this way, it is convenient to connect adjacent second battery cells 31 in series. The total positive pole and the total negative pole of the second battery group 3 are led out on the same side, and are arranged on opposite sides with the total positive pole and the total negative pole of the first battery group 2.

[0052] In some embodiments, the first battery pack 2 and the second battery pack 3 are both welded on the same side. The difference from the above embodiments lies in the structure of the second battery cell 31, which is set to be similar to the first battery cell 21, that is, a positive pole is provided at one end, the shell is negatively charged, the shell includes an end cover at one end, the end cover and the positive pole are located at the same end, and the second battery cell 31 is welded on the same side, and the positive pole of one second battery cell 31 is welded to the end cover of another adjacent second battery cell 31 to achieve series connection. In this way, the first battery pack 2 and the second battery pack 3 can be welded on the same side.

[0053] In some embodiments, a second gap 32 exists between adjacent first battery cells 21 and second battery cells 31 , and the second gap 32 is filled with a heat-insulating member 45 .

[0054] By providing a heat-insulating insulating member 45 in the second gap 32 between the first battery cell 21 and the second battery cell 31, it can play a role in heat insulation and insulation when a battery cell has thermal runaway, thereby preventing heat from spreading to adjacent battery cells and causing fire, and can effectively control the spread of thermal runaway and improve the safety performance of the battery pack.

[0055] Specifically, the heat-insulating member 45 includes insulating foam, mica sheet or aerogel.

[0056] In some embodiments, a support member 46 is provided at a corner of the battery pack, and the support member 46 includes an insulating member and / or a heat insulating member.

[0057] Specifically, support members 46 are provided at the corners of the battery pack, and the support members 46 are one or a combination of insulating members and heat insulating members. In this way, when thermal runaway occurs in the battery pack, the support members 46 can play an insulating and / or heat insulating role, reduce the spread of thermal runaway, and improve the safety performance of the battery pack. In addition, the support members 46 provided at the corners of the battery pack can also play a role of rigid support. In some embodiments, such as Figure 2 As shown, two corners of the battery pack are provided with support members 46. In other embodiments, such as Figure 4 As shown, support members 46 are provided at the four corners of the battery pack.

[0058] Furthermore, the support member 46 includes one or a combination of insulating gasket, rubber, mica sheet, and aerogel.

[0059] In some embodiments, there is a second gap 32 between adjacent first battery cells 21 and second battery cells 31; a thermal runaway monitoring device is also included, which includes at least one pressure sensor 5 arranged in the second gap 32, and the pressure sensor 5 is arranged at an axial interval along the first battery cell 21, and the pressure sensor 5 is abutted against the outer peripheral walls of the three adjacent battery cells.

[0060] The battery pack provided in this embodiment is also provided with a thermal runaway monitoring device. By setting a pressure sensor 5, the pressure sensor 5 is in contact with the outer peripheral walls of the three battery cells. In this way, one pressure sensor 5 can simultaneously test the pressure of three adjacent cells and detect the displacement values ​​X1, X2 and X3 of the outer peripheral walls of the three battery cells at the contact point. Since at least one pressure sensor 5 is arranged at intervals along the axial direction of the first battery cell 21, taking three as an example, each battery cell is compared by the displacement data of the three pressure sensors 5 located at the upper, middle and lower parts to obtain the expansion trend of different parts of the battery cell. In theory, during the charging and discharging process of the battery cell, the expansion of the pole piece is uniform. If an abnormality occurs in one of the values, such as the difference between X1, X2 and X3 exceeds a preset ratio, it can be regarded as a failure at a certain position inside the battery cell, causing uneven expansion of the battery cell, thereby judging that the battery cell has a risk of failure. The pressure data of the pressure sensor 5 is fed back to the BMS control module via communication. When an abnormal pressure occurs in one of the cells in the two battery packs, the battery pack circuit switch can be disconnected to stop the battery pack from being used further. Or it can be switched to other power sources (such as backup power sources) or auxiliary power circuits, while continuing to monitor other battery information, such as temperature, voltage, abnormal gas, etc. In this way, when used as other power sources or auxiliary sources, the output current is usually small, and the risk of loss of control is small. On the other hand, under low risk, the battery pack continues to be used as an auxiliary source, which can also avoid misjudgment caused by a single pressure detection data, resulting in the battery pack not being put into use.

[0061] Furthermore, in some embodiments, when multiple pressure sensors 5 are arranged at intervals along the axial direction of the first battery cell 21, taking three as an example, the three pressure sensors 5 will detect the displacement values ​​X1, X2 and X3 of different cells at the same position, and will also detect the displacement values ​​of different positions of the same cell, such as X11, X12 and X13. When the difference between X11, X12 and X13 exceeds a preset ratio, it can also be regarded as a failure at a certain position inside the battery cell, causing uneven expansion of the battery cell, thereby judging that the battery cell is at risk of failure.

[0062] Furthermore, on the basis of the pressure sensor 5 being fixed, the remaining space of the second gap 32 can be filled with aerogel or thermally conductive silica gel, etc. Alternatively, the foam, aerogel or thermally conductive structural adhesive is made into a structure matching the second gap 32, and the pressure sensor 5 is embedded inside, which greatly utilizes the battery pack space and improves the safety performance of the battery pack.

[0063] In some embodiments, the pressure sensor 5 is adhesively connected to the first battery cell 21 and the second battery cell 31; or, it also includes a fixing frame 6, the fixing frame 6 includes a first hole position 61, a second hole position 62 and at least one mounting groove 63, the first battery cell 21 is arranged at the first hole position 61, the second battery cell 31 is arranged at the second hole position 62, and each pressure sensor 5 is arranged in a mounting groove 63.

[0064] Specifically, the pressure sensor 5 can be fixed to the first battery cell 21 and the second battery cell 31 by dispensing or pouring structural glue.

[0065] Since at least one pressure sensor 5 is provided, when the fixing frame 6 is used for installation, the fixing frame 6 is provided with a corresponding number of installation layers, and multiple pressure sensors 5 are respectively installed on multiple installation layers. Specifically, in one embodiment, the fixing frame 6 is provided with an installation groove 63, the installation groove 63 is provided with an internal thread, the outer wall of the pressure sensor 5 is provided with an external thread, and the pressure sensor 5 is threadedly connected to the installation groove 63 of the fixing frame 6.

[0066] According to an embodiment of the present invention, on the other hand, a battery system is provided, comprising a BMS control module, an energy conversion module and a battery pack according to any one of the above embodiments. The battery pack supplies power to the BMS control module and / or the energy conversion module.

[0067] The battery system provided by the present invention includes the battery pack in the above-mentioned embodiment. By integrating the dual battery groups into a battery system, the volume of the battery pack is utilized to the greatest extent, thereby improving the overall energy density of the battery system. Through flexible control, a set of products can meet different power demands, and can be switched for use when any battery group has abnormal pressure. This is more flexible and convenient, fully utilizes the battery group, has low cost, improves service life and system safety performance, and has high economic value.

[0068] Specifically, the energy conversion module includes an inverter.

[0069] In some embodiments, the first battery pack and the second battery pack in the battery pack are controlled by the BMS control module through communication; the first battery pack 2 of the battery pack is conductively connected to the energy conversion module, and the second battery pack 3 of the battery pack is conductively connected to the BMS control module; or the first battery pack and the second battery pack of the battery pack are conductively connected to the energy conversion module. Figures 10 to 12 As shown, it will be introduced in detail later.

[0070] In some embodiments, a switching switch is also included, one end of the switching switch is conductively connected to the energy conversion module, and the other end of the switching switch is provided with a first switch position and a second switch position. In the first switch position, the switching switch is conductively connected to the first battery group 2, and in the second switch position, the switching switch is conductively connected to the second battery group 3; the pressure sensor 5 of the battery pack is communicatively connected to the BMS control module, and is used to transmit pressure data to the BMS control module. The BMS control module determines whether there is a pressure abnormality in the first battery group 2 or the second battery group 3 based on the pressure data. When there is a pressure abnormality in either the first battery group 2 or the second battery group 3, the BMS control module can cut off the power supply circuit of the battery group, or switch the switching switch to another switch position.

[0071] In some embodiments, it also includes a first compound switch and a second compound switch. In a first working state, the first battery group 2 is conductively connected to the energy conversion module through the first compound switch, and the second battery group 3 is conductively connected to the BMS control module through the second compound switch; in a second working state, the second battery group 3 is conductively connected to the energy conversion module through the first compound switch, and the first battery group 2 is conductively connected to the BMS control module through the second compound switch. The battery system is suitable for arbitrarily switching between the first working state and the second working state.

[0072] Specifically, in some embodiments, the first working state is a normal working state, and the second working state is a state where the performance of the first battery pack 2 is degraded. The switching timing between the first working state and the second working state can be determined according to actual working requirements.

[0073] Three different battery pack control schemes are provided below.

[0074] In some embodiments, Figures 10 to 12 shown.

[0075] The switching switch includes a positive contact and a negative contact, the positive contact is conductively connected to the positive end of the energy conversion module, and the negative contact is conductively connected to the negative end of the energy conversion module.

[0076] The first switch position is provided with a positive contact B11 and a negative contact B12 , the positive contact B11 is conductively connected to the first positive lead 24 of the first battery pack 2 , and the negative contact B12 is conductively connected to the first negative lead 25 of the first battery pack 2 .

[0077] The second switch position is provided with a positive contact B21 and a negative contact B22. The positive contact B21 is conductively connected to the second positive lead-out line 34 of the second battery pack 3, and the negative contact B22 is conductively connected to the second negative lead-out line 35 of the second battery pack 3.

[0078] When the switch is turned to the first switch position, the positive contact and the positive contact B11 are conductively connected, and the negative contact and the negative contact B12 are conductively connected. At this time, the first battery group 2 is connected to the energy conversion module as an energy storage power source.

[0079] When the switch is turned to the second switch position, the positive contact and the positive contact B21 are conductively connected, and the negative contact and the negative contact B22 are conductively connected. At this time, the second battery pack 3 is connected to the BMS control module as a portable power source.

[0080] In this embodiment, the battery pack output mode is switched between the first battery pack 2 and the second battery pack 3 by a switching switch to achieve the power demand of different scenarios. For example, the switching switch is connected to the first battery pack 2 for household battery storage. Or, the switching switch is connected to the second battery pack 3 as a portable power source. In this way, the first battery pack 2 and the second battery pack 3 can be used as an energy storage power source and a portable power source respectively, which improves the overall energy density of the system, and there are two sets of solutions in a battery system to match different application requirements, which is more flexible.

[0081] In some embodiments, Fig.13 The first battery pack 2 is used as an energy storage power source, and the second battery pack 3 is used as an auxiliary power source to provide power for other components in the battery system such as a BMS control module.

[0082] Specifically, the first positive lead wire 24 of the first battery group 2 is conductively connected to the positive terminal of the energy conversion module, and the first negative lead wire 25 of the first battery group 2 is conductively connected to the negative terminal of the energy conversion module.

[0083] The second positive lead wire 34 of the second battery pack 3 is conductively connected to the positive terminal of the BMS control module, and the second negative lead wire 35 of the second battery pack 3 is conductively connected to the negative terminal of the BMS control module.

[0084] This arrangement, on the one hand, avoids wasting space by connecting an external power source, and on the other hand, replaces the traditional energy storage battery pack, serving as both an energy storage power source and the power source of the battery pack itself, reducing the self-consumption of the first battery group 2, and avoiding the state of self-consumption of the first battery group 2, thereby improving the performance and life of the first battery group 2. And without adding an external auxiliary power source, the battery pack space is utilized to improve the energy density of the battery system.

[0085] In some embodiments, Figures 14 to 16 As shown, a first composite switch S1 and a second composite switch S2 are provided.

[0086] Specifically,

[0087] The first composite switch S1 is connected to the energy conversion module, and the first composite switch S1 includes a positive contact a and a negative contact b.

[0088] The second composite switch S2 is connected to the BMS control module, and includes a positive contact c and a negative contact d.

[0089] Under normal working conditions, the first battery pack 2 serves as an energy storage power source, and the second battery pack 3 serves as an auxiliary power source.

[0090] Specifically:

[0091] The positive contact a of the first combined switch S1 is conductively connected to the positive contact B11 of the first switch position, and the negative contact b of the first combined switch S1 is conductively connected to the negative contact B12 of the first switch position.

[0092] The positive contact c of the second combined switch S2 is conductively connected to the positive contact B21 of the second switch position, and the negative contact d of the second combined switch S2 is conductively connected to the negative contact B22 of the second switch position.

[0093] When the performance of the first battery pack 2 decreases, the first composite switch S1 and the second composite switch S2 are switched, so that the second battery pack 3 is used as an energy storage power source and the first battery pack 2 is used as an auxiliary power source. Specifically:

[0094] The positive contact a of the first combined switch S1 is conductively connected to the positive contact B21 of the second switch position, and the negative contact b of the first combined switch S1 is conductively connected to the negative contact B22 of the second switch position.

[0095] The positive contact c of the second composite switch S2 is conductively connected to the positive contact B11 of the first switch position, and the negative contact d of the second composite switch S2 is electrically connected to the negative contact B12 of the first switch position.

[0096] In this way, it is possible to flexibly switch between the first battery pack 2 and the second battery pack 3 to control the operation of the battery system, thereby reducing operation and maintenance costs, increasing service life, and making usage scenarios more flexible.

[0097] The battery pack provided in the embodiment of the present invention integrates dual battery groups into a battery system to maximize the use of the battery pack volume and improve the overall energy density of the battery system. Through flexible control, a set of products can meet different power demands and can be switched for use when abnormal pressure exists in any battery group. This is more flexible and convenient, fully utilizes the battery group, has low cost, improves service life and system safety performance, and has high economic value.

[0098] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A battery pack, characterized in that: It comprises a housing (1) and: A first battery group (2), the first battery group (2) comprising a plurality of first battery cells (21) connected in series, the plurality of first battery cells (21) being closely arranged in a manner of axis parallel, and a first gap (22) being present between four adjacent first battery cells (21) or between two adjacent first battery cells (21) and the housing (1); A second battery group (3), the second battery group (3) comprising a plurality of second battery cells (31) connected in series, the diameter of the second battery cells (31) being smaller than the diameter of the first battery cells (21), and each of the second battery cells (31) being arranged in one of the first gaps (22).

2. The battery pack according to claim 1, characterized in that: The radius of the first battery cell (21) is r1, the radius of the second battery cell (31) is r2, and r2≤(√2-1)×r1.

3. The battery pack according to claim 1 or 2, characterized in that: In the first battery group (2), adjacent first battery cells (21) are connected in series via palladium sheets (23), and a first positive electrode lead wire (24) and a first negative electrode lead wire (25) are provided on a first end surface of the first battery group (2); In the second battery group (3), adjacent second battery cells (31) are connected in series via a wire (33), and a second positive electrode lead wire (34) and a second negative electrode lead wire (35) are provided on a second end surface of the second battery group (3); The second end surface is arranged opposite to the first end surface.

4. The battery pack according to claim 3, characterized in that: A second gap (32) exists between the adjacent first battery cells (21) and the second battery cells (31); The invention also comprises a thermal runaway monitoring device, the thermal runaway monitoring device comprising at least one pressure sensor (5) arranged in the second gap (32), the pressure sensor (5) being arranged at intervals along the axial direction of the first battery cell (21), and the pressure sensor (5) being in contact with the outer peripheral walls of three adjacent battery cells.

5. The battery pack according to claim 4, characterized in that: The pressure sensor (5) is adhesively connected to the first battery cell (21) and the second battery cell (31); Alternatively, the invention further comprises a fixing frame (6), wherein the fixing frame (6) comprises a first hole position (61), a second hole position (62) and at least one mounting groove (63), the first battery cell (21) is arranged in the first hole position (61), the second battery cell (31) is arranged in the second hole position (62), and each of the pressure sensors (5) is arranged in one of the mounting grooves (63).

6. The battery pack according to claim 5, characterized in that: It also includes a first insulating sheet (41) and a second insulating sheet (42), wherein the first insulating sheet (41) is arranged on the first end surface, and the second insulating sheet (42) is arranged on the second end surface; The first insulating sheet (41) is provided with a plurality of first welding through holes (43) and a plurality of second welding through holes (44), the second insulating sheet (42) is provided with a plurality of second welding through holes (44), the first welding through holes (43) being used for welding adjacent first battery cells (21) in series, and the second welding through holes (44) being used for welding adjacent second battery cells (31) in series; Alternatively, the first insulating sheet (41) is provided with a plurality of first welding through holes (43), and the second insulating sheet (42) is provided with a plurality of second welding through holes (44), the first welding through holes (43) being used to weld adjacent first battery cells (21) in series, and the second welding through holes (44) being used to weld adjacent second battery cells (31) in series.

7. A battery system, characterized in that: include: BMS control module; Energy conversion module; The battery pack according to any one of claims 1 to 6, wherein the battery pack supplies power to the BMS control module and / or the energy conversion module.

8. The battery system according to claim 7, characterized in that: The first battery pack and the second battery pack in the battery pack are controlled in working state by the BMS control module through communication; The first battery group (2) of the battery pack is conductively connected to the energy conversion module, and the second battery group (3) of the battery pack is conductively connected to the BMS control module; or both the first battery group (2) and the second battery group (3) of the battery pack are conductively connected to the energy conversion module.

9. The battery system according to claim 7, characterized in that: The battery system further comprises a first composite switch and a second composite switch. In a first working state, the first battery group (2) is conductively connected to the energy conversion module via the first composite switch, and the second battery group (3) is conductively connected to the BMS control module via the second composite switch. In a second working state, the second battery group (3) is conductively connected to the energy conversion module via the first composite switch, and the first battery group (2) is conductively connected to the BMS control module via the second composite switch. The battery system is suitable for arbitrarily switching between the first working state and the second working state.

10. The battery system according to claim 7, characterized in that: The invention also comprises a switching switch, one end of which is conductively connected to the energy conversion module, and the other end of which is provided with a first switch position and a second switch position. In the first switch position, the switching switch is conductively connected to the first battery pack (2), and in the second switch position, the switching switch is conductively connected to the second battery pack (3). The pressure sensor (5) of the battery pack is communicatively connected to the BMS control module and is used to transmit pressure data to the BMS control module. The BMS control module determines whether there is a pressure abnormality in the first battery pack (2) or the second battery pack (3) based on the pressure data. When there is a pressure abnormality in either the first battery pack (2) or the second battery pack (3), the BMS control module can cut off the power supply circuit of the battery pack or switch the switching switch to another switch position.

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