Power battery, series-parallel connection control method of power battery and fault control method of power battery

Abstract

The invention belongs to the technical field of electric vehicles, and particularly relates to a power battery, a series-parallel connection control method of the power battery and a fault control method of the power battery, and the power battery comprises a positive electrode circuit, a negative electrode circuit, a switching circuit and a plurality of battery assemblies; each battery assembly comprises a first battery cell and a second battery cell; all first battery cells and all second battery cells contained in the power battery are connected with the switching circuit; the plurality of battery assemblies are arranged in sequence, the positive electrode circuit is connected with the positive electrode of the first battery cell of the first battery assembly, and the negative electrode circuit is connected with the negative electrode of the second battery cell of the last battery assembly; the switching circuit is used for switching a communication mode between a plurality of first battery cells and a plurality of second battery cells contained in the power battery to obtain a first circuit structure or a second circuit structure, so that the power battery can be switched between a high-voltage platform and a low-voltage platform.

Description

Technical Field

[0001] This invention belongs to the field of electric vehicle technology, specifically relating to a power battery, a series-parallel control method for the power battery, and a fault control method. Background Technology

[0002] For electric vehicles, increasing the voltage of the electric drive system can significantly reduce the internal resistance loss of the electric drive system under the same power demand, improve the efficiency of the high-speed system, and further reduce the battery capacity required to achieve the same driving range, thereby reducing battery costs and overall vehicle weight. In addition, increasing the voltage can also improve charging efficiency, shorten charging time, and greatly improve the user experience of electric vehicles. Therefore, the development of power battery voltage platforms from low voltage platforms (usually 400V) to high voltage platforms, with 800V or even higher levels becoming the industry's development direction.

[0003] However, due to the more mature supply chain of low-voltage platform vehicles, the fact that high-rate charging accelerates battery degradation, and the problems of regional imbalance, insufficient technical compatibility, and supply-demand mismatch in the development of supercharging piles, the current market for high-voltage platform vehicles using full high-voltage architecture (overall system 800V design, optimal efficiency but higher cost) and partial high-voltage architecture (only the battery is upgraded to 800V, other components retain 400V, balancing performance and modification costs) cannot keep pace with the popularization of supercharging piles adapted to high-voltage platforms. As a result, high-voltage platform vehicles still have shortcomings in the balance between charging convenience, performance, and development costs. Summary of the Invention

[0004] To address the shortcomings of the existing technology, this invention provides a power battery, a series-parallel control method for the power battery, and a fault control method to solve the technical problems that current high-voltage platform vehicles still lack in terms of charging convenience, performance, and the balance between development costs.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: a power battery, comprising a positive electrode circuit, a negative electrode circuit, a switching circuit, and multiple battery components; each battery component includes a first battery cell and a second battery cell; all the first battery cells and all the second battery cells included in the power battery are connected to the switching circuit; Multiple battery modules are arranged sequentially, with the positive electrode circuit connected to the positive electrode of the first cell of the first battery module and the negative electrode circuit connected to the negative electrode of the second cell of the last battery module. The switching circuit is used to switch the connection mode between the plurality of first cells and the plurality of second cells contained in the power battery to obtain a first circuit structure or a second circuit structure. The first circuit structure includes a first battery unit and a second battery unit. The first battery unit is composed of all the first cells contained in the power battery connected in parallel. The second battery unit is composed of all the second cells contained in the power battery connected in parallel. The negative terminal of the first battery unit is connected to the positive terminal of the second battery unit. The second circuit structure includes all the battery components contained in the power battery connected in series in the arrangement order, and the negative terminal of the first cell of any battery component is connected to the positive terminal of the second cell of the same battery component. In two adjacent battery components, the negative terminal of the second cell of the preceding battery component is connected to the positive terminal of the first cell of the following battery component.

[0006] By setting the switching circuit to switch the connection mode between the multiple first cells and multiple second cells included in the power battery, a first circuit structure or a second circuit structure is obtained; this enables the power battery provided by the present invention to switch between a high-voltage platform (i.e., when switching to the second circuit structure) and a low-voltage platform (i.e., when switching to the first circuit structure), so that electric vehicles using the power battery provided by the present invention can be compatible with both supercharging piles and low-voltage charging piles, and can also be compatible with the supply chain of existing low-voltage platform models during vehicle development; during charging, it can balance the high efficiency of high-voltage charging and the charging convenience of low-voltage charging, and can also help developers balance performance and modification costs during vehicle development, solving the technical problem that current high-voltage platform models still have shortcomings in the balance between charging convenience, performance and development costs.

[0007] Furthermore, the power battery provided by this invention can adjust the ratio between the high-voltage platform (i.e., the voltage of the power battery when switching to the second circuit structure) and the low-voltage platform (i.e., the voltage of the power battery when switching to the first circuit structure) by adjusting the number of battery components during the development process. This allows the power battery provided by this invention to be free from the current limitation of high-voltage platform development being mostly limited to the 800V voltage level, giving it a great degree of development freedom. It can adapt to the future development direction of high-voltage platforms towards 800V and above, and can better adapt to the future development direction of the industry.

[0008] Furthermore, the switching circuit includes a first parallel sub-circuit, a second parallel sub-circuit, a first series line, a second series line, a first relay, and a second relay; All of the first cells are connected to the first parallel sub-circuit, which is used to connect all the first cells in parallel or disconnect all the first cells in parallel. All of the second cells are connected to the second parallel sub-circuit, which is used to connect all the second cells in parallel or disconnect all the second cells in parallel. In any two adjacent battery modules, a first series circuit is connected between the negative terminal of the second cell of the preceding battery module and the positive terminal of the first cell of the following battery module, and a second series circuit is connected between the negative terminal of the first cell and the positive terminal of the second cell of each battery module; a first relay is provided on each first series circuit, and a second relay is provided on each second series circuit.

[0009] In one technical solution, the power battery includes at least three battery modules; the first parallel sub-circuit includes a first line, a second line, a first connecting line, a second connecting line, a third relay, and a fourth relay; each first cell has a corresponding first connecting line connected to its positive terminal, with one end of each first connecting line connected to the positive terminal of the corresponding first cell and the other end connected to the first line; each first cell has a corresponding second connecting line connected to its negative terminal, with one end of each second connecting line connected to the negative terminal of the corresponding first cell and the other end connected to the second line; each first connecting line has a third relay, and each second connecting line has a fourth relay. The second parallel sub-circuit includes a third line, a fourth line, a third connecting line, a fourth connecting line, a fifth relay, and a sixth relay; each of the second battery cells has a corresponding third connecting line connected to its positive terminal, with one end of each third connecting line connected to the positive terminal of the corresponding second battery cell and the other end connected to the third line; each of the second battery cells has a corresponding fourth connecting line connected to its negative terminal, with one end of each fourth connecting line connected to the negative terminal of the corresponding second battery cell and the other end connected to the fourth line; each of the third connecting lines has a fifth relay, and each of the fourth connecting lines has a sixth relay.

[0010] The above technical solution provides a specific structure for a power battery where the ratio between the high-voltage platform (i.e., the voltage of the power battery when switching to the second circuit structure) and the low-voltage platform (i.e., the voltage of the power battery when switching to the first circuit structure) is at least three times. This allows the power battery to switch between the first circuit structure and the second circuit structure by adjusting the on / off states of each of the first relays, each of the second relays, each of the third relays, each of the fourth relays, each of the fifth relays, and each of the sixth relays. Furthermore, it enables the power battery to switch to the first circuit structure and control the on / off states of each of the first, second, third, fourth, fifth, and sixth relays in the event of a failure in any of the first or second battery cells. By using four relays or each of the aforementioned fifth relays to isolate the faulty first or second battery cell (for example, but not limited to: controlling the second relay connected to any one of the second series lines between the faultless first and second battery cells to close, and controlling the second relay connected to the faulty first or second battery cell to open; then controlling the fourth relay on the second connection line corresponding to the faulty first battery cell to open, or controlling the fifth relay on the third connection line corresponding to the faulty second battery cell to open), the power battery can ensure that it can operate stably in low-voltage platform mode while isolating the faulty first or second battery cell and losing only the capacity of one battery cell.

[0011] In another technical solution, the power battery includes two battery modules; the first parallel sub-circuit includes a fifth line, a sixth line, a seventh relay, and an eighth relay; One end of the fifth line is connected to the positive terminal of one of the first cells, and the other end of the fifth line is connected to the positive terminal of the other first cell; one end of the sixth line is connected to the negative terminal of one of the first cells, and the other end of the sixth line is connected to the negative terminal of the other first cell. The seventh relay is installed on the fifth line, and the eighth relay is installed on the sixth line; The second parallel sub-circuit includes a seventh line, an eighth line, a ninth relay, and a tenth relay; One end of the seventh line is connected to the positive terminal of one of the second cells, and the other end of the seventh line is connected to the positive terminal of the other second cell; one end of the eighth line is connected to the negative terminal of one of the second cells, and the other end of the eighth line is connected to the negative terminal of the other second cell. The ninth relay is installed on the seventh line, and the tenth relay is installed on the eighth line.

[0012] The above technical solution provides a specific structure for a power battery with a voltage ratio of twice that of a high-voltage platform (i.e., the voltage of the power battery when switching to the second circuit structure) and a low-voltage platform (i.e., the voltage of the power battery when switching to the first circuit structure). This allows the power battery to switch between the first circuit structure and the second circuit structure by adjusting the on / off states of each of the first relays, each of the second electrical components, the seventh relay, the eighth relay, the ninth relay, and the tenth relay. Furthermore, it enables the power battery to switch back to the first circuit structure and then control the power battery in the event of a failure in any of the first or second battery cells. By controlling the eighth or ninth relay to isolate the faulty first or second battery cell (for example, but not limited to: controlling the second relay connected to any one of the second series lines between the faultless first and second battery cells to close, and controlling the second relay connected to the faulty first or second battery cell to open; controlling the eighth relay to open when the first battery cell fails, and controlling the ninth relay to open when the second battery cell fails), it can be ensured that the power battery can operate stably in low-voltage platform mode while isolating the faulty first or second battery cell and losing only the capacity of one battery cell.

[0013] According to the power battery provided by the present invention, the present invention also provides a series-parallel control method for the power battery, the series-parallel control method comprising: Obtain high-voltage platform mode information or low-voltage platform mode information; Based on the obtained low-voltage platform mode information, the control switching circuit switches the connection mode between the multiple first cells and multiple second cells contained in the power battery to obtain the first circuit structure; Based on the obtained high-voltage platform mode information, the control switching circuit switches the connection mode between the multiple first cells and multiple second cells contained in the power battery to obtain a second circuit structure.

[0014] Furthermore, the method for obtaining the first circuit structure includes: All first relays of the switching circuit are disconnected, one second relay of the switching circuit is closed, and the remaining second relays of the switching circuit are disconnected. The first parallel sub-circuit controlling the switching circuit connects all the first cells in parallel, and the second parallel sub-circuit controlling the switching circuit connects all the second cells in parallel.

[0015] In one of the technical solutions, corresponding to the aforementioned power battery comprising at least three battery modules, the method for controlling the first parallel sub-circuit to connect all the first cells in parallel includes: All third and fourth relays controlling the first parallel sub-circuit are closed; The method of controlling the second parallel sub-circuit to connect all the second cells in parallel includes: All fifth and sixth relays controlling the second parallel sub-circuit are closed.

[0016] In another technical solution, corresponding to the aforementioned power battery comprising two battery modules, the method for controlling the first parallel sub-circuit to connect all the first cells in parallel includes: Both the seventh and eighth relays controlling the first parallel sub-circuit are closed.

[0017] The method of controlling the second parallel sub-circuit to connect all the second cells in parallel includes: The ninth and tenth relays controlling the second parallel sub-circuit are both closed.

[0018] Furthermore, the method for obtaining the second circuit structure includes: The first parallel sub-circuit of the switching circuit controls all the first cells to be disconnected and connected in parallel, and the second parallel sub-circuit of the switching circuit controls all the second cells to be disconnected and connected in parallel. All first relays and all second relays controlling the switching circuit are closed.

[0019] In one of the technical solutions, corresponding to the aforementioned power battery comprising at least three battery modules, the method for controlling the first parallel sub-circuit to disconnect and connect all the first cells in parallel includes: All third and fourth relays controlling the first parallel sub-circuit are disconnected; The method of controlling the second parallel sub-circuit to disconnect and connect all the second cells in parallel includes: All fifth and sixth relays controlling the second parallel sub-circuit are disconnected.

[0020] In another technical solution, corresponding to the aforementioned power battery comprising two battery modules, the method for controlling the first parallel sub-circuit to disconnect and connect all the first cells in parallel includes: The seventh and eighth relays controlling the first parallel sub-circuit are both disconnected.

[0021] The method of controlling the second parallel sub-circuit to disconnect and connect all the second cells in parallel includes: The ninth and tenth relays controlling the second parallel sub-circuit are both disconnected.

[0022] According to the power battery provided by the present invention, the present invention also provides a fault control method for the power battery, the fault control scheme being applicable to the technical solution of the power battery provided by the present invention including at least three battery components; The fault control method includes: Obtain first fault information indicating that any first cell of the power battery has failed, or second fault information indicating that any second cell has failed; Based on the obtained first fault information or second fault information, the control switching circuit switches the connection mode between the multiple first cells and multiple second cells contained in the power battery to obtain a first circuit structure; Then, based on the obtained first fault information, control the fourth relay on the second connection line corresponding to the faulty first battery cell to disconnect, or control the fifth relay on the third connection line corresponding to the faulty second battery cell to disconnect based on the obtained second fault information. The method for obtaining the first circuit structure is as follows: control all the first relays of the switching circuit to be disconnected, control any one of the second relays in the switching circuit connected to the second series line between the first battery cell that has not failed and the second battery cell that has not failed to be closed, and control the remaining second relays to be disconnected; control all the third and fourth relays of the first parallel sub-circuit of the switching circuit, and all the fifth and sixth relays of the second parallel sub-circuit of the switching circuit to be closed.

[0023] According to the power battery provided by the present invention, the present invention also provides a fault control method for the power battery, the fault control scheme being applicable to the technical solution of the power battery provided by the present invention including two battery components; The fault control method includes: Obtain first fault information indicating that any first cell of the power battery has failed, or second fault information indicating that any second cell has failed; Based on the obtained first fault information or second fault information, the control switching circuit switches the connection mode between the multiple first cells and multiple second cells contained in the power battery to obtain a first circuit structure; Then, based on the obtained first fault information, control the eighth relay of the first parallel sub-circuit of the switching circuit to disconnect, or control the ninth relay of the second parallel sub-circuit of the switching circuit to disconnect based on the obtained second fault information. The method for obtaining the first circuit structure is as follows: control all the first relays of the switching circuit to be disconnected, control the second relays in the second series line connected between the first battery cell and the second battery cell that has not failed to close to be closed, and control another second relay to be disconnected; control the seventh and eighth relays of the first parallel sub-circuit of the switching circuit, as well as the ninth and tenth relays of the second parallel sub-circuit of the switching circuit to be closed.

[0024] According to the power battery provided by the present invention, the present invention also provides a fault control method for the power battery, the fault control scheme being applicable to the technical solution of the power battery provided by the present invention including two battery components; The fault control method includes: Obtain first fault information indicating that any first cell of the power battery has failed, or second fault information indicating that any second cell has failed; Based on the obtained first fault information or second fault information, the system controls the first relay of the switching circuit to open, controls the second relay in the second series line connected between the first battery cell and the second battery cell that has not experienced a fault to close, and controls the other second relay to open; then controls the eighth relay of the first parallel sub-circuit of the switching circuit and the ninth relay of the second parallel sub-circuit of the switching circuit to open, and controls the seventh relay of the first parallel sub-circuit and the tenth relay of the second parallel sub-circuit to close.

[0025] By disconnecting the first relay, closing the second relay on the second series circuit between the first and second cells that are not faulty, disconnecting the other second relay, and then disconnecting the eighth and ninth relays and closing the seventh and tenth relays, only one first cell and one second cell that are not faulty can be connected in series sequentially between the positive and negative circuits of the power battery. Although this will cause the power battery to additionally isolate the first or second cell that is not faulty in the same battery pack when isolating the first or second cell that is faulty, resulting in a loss of capacity of two cells, it can also avoid the problem of uneven distribution of charging and discharging current caused by the difference in consistency of the cells when two cells are connected in parallel and then another cell is connected in series between the positive and negative circuits, which would affect the cell life and reliability of the power battery. Attached Figure Description

[0026] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the power battery structure in Example 1; Figure 2 This is a schematic diagram of the power battery structure in Example 2; Figure 3 This is a schematic diagram of the first circuit structure in Embodiment 3. Figure 1 ; Figure 4 This is a schematic diagram of the first circuit structure in Embodiment 3. Figure 2 ; Figure 5 This is a schematic diagram of the second circuit structure in Embodiment 3. Figure 1 ; Figure 6 This is a schematic diagram of the second circuit structure in Embodiment 3. Figure 2 ; Figure 7 This is a schematic diagram of the final circuit structure of the power battery obtained according to the fault control method in Example 4. Figure 1 ; Figure 8 This is a schematic diagram of the final circuit structure of the power battery obtained according to the fault control method in Example 4. Figure 2 ; Figure 9 This is a schematic diagram of the final circuit structure of the power battery obtained according to the fault control method in Example 5. Figure 1 ; Figure 10 This is a schematic diagram of the final circuit structure of the power battery obtained according to the fault control method in Example 5. Figure 2 ; Figure 11 This is a schematic diagram of the final circuit structure of the power battery obtained according to the fault control method in Example 6; Among them, 1—positive circuit, 2—negative circuit, 3—first battery cell, 4—second battery cell, 5—first relay, 6—second relay, 7—third relay, 8—fourth relay, 9—fifth relay, 10—sixth relay, 11—seventh relay, 12—eighth relay, 13—ninth relay, and 14—tenth relay. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0029] Example 1: like Figure 1 As shown, this embodiment 1 provides a power battery, including a positive electrode circuit 1, a negative electrode circuit 2, a switching circuit, and multiple battery components; each battery component includes a first cell 3 and a second cell 4; all the first cells 3 and all the second cells 4 in the power battery are connected to the switching circuit; Multiple battery modules are arranged sequentially. The positive circuit 1 is connected to the positive terminal of the first cell 3 of the first battery module, and the negative circuit 2 is connected to the negative terminal of the second cell 4 of the last battery module. The switching circuit is used to switch the connection mode between the multiple first cells 3 and multiple second cells 4 contained in the power battery to obtain a first circuit structure or a second circuit structure. The first circuit structure includes a first battery unit and a second battery unit. The first battery unit is composed of all the first cells 3 contained in the power battery connected in parallel. The second battery unit is composed of all the second cells 4 contained in the power battery connected in parallel. The negative terminal of the first battery unit is connected to the positive terminal of the second battery unit. The second circuit structure includes all the battery components contained in the power battery connected in series in the layout order, and the negative terminal of the first cell 3 of any battery component is connected to the positive terminal of the second cell 4 of the same battery component. In two adjacent battery components, the negative terminal of the second cell 4 of the previous battery component is connected to the positive terminal of the first cell 3 of the next battery component.

[0030] By setting a switching circuit to switch the connection mode between the multiple first cells 3 and multiple second cells 4 contained in the power battery, a first circuit structure or a second circuit structure is obtained; this allows the power battery provided by the present invention to switch between a high-voltage platform (i.e., when switching to the second circuit structure) and a low-voltage platform (i.e., when switching to the first circuit structure), enabling electric vehicles using the power battery provided by the present invention to be compatible with both supercharging piles and low-voltage charging piles, and also compatible with the supply chain of existing low-voltage platform models during vehicle development; during charging, it can balance the efficiency of high-voltage charging and the convenience of low-voltage charging, and also facilitates developers to balance performance and modification costs during vehicle development, solving the technical problem that current high-voltage platform models still have shortcomings in the balance between charging convenience, performance and development costs.

[0031] Furthermore, the power battery provided by this invention can adjust the ratio between the high-voltage platform (i.e., the voltage of the power battery when switching to the second circuit structure) and the low-voltage platform (i.e., the voltage of the power battery when switching to the first circuit structure) by adjusting the number of battery components during the development process. This allows the power battery provided by this invention to be free from the current limitation of high-voltage platform development being mostly limited to the 800V voltage level, giving it a great degree of development freedom. It can adapt to the future development direction of high-voltage platforms towards 800V and above, and can better adapt to the future development direction of the industry.

[0032] In one embodiment, such as Figure 1 As shown, the switching circuit includes a first parallel sub-circuit, a second parallel sub-circuit, a first series line, a second series line, a first relay 5, and a second relay 6. All the first cells 3 are connected to the first parallel sub-circuit, which is used to connect all the first cells 3 in parallel or disconnect all the first cells 3 in parallel. All the second cells 4 are connected to the second parallel sub-circuit, which is used to connect all the second cells 4 in parallel or disconnect all the second cells 4 in parallel. In any two adjacent battery modules, a first series circuit is connected between the negative terminal of the second cell 4 of the preceding battery module and the positive terminal of the first cell 3 of the following battery module, and a second series circuit is connected between the negative terminal of the first cell 3 and the positive terminal of the second cell 4 of each battery module; a first relay 5 is provided on each first series circuit, and a second relay 6 is provided on each second series circuit.

[0033] Specifically, in this embodiment 1, as follows Figure 1 As shown, the power battery includes at least three battery modules; the first parallel sub-circuit includes a first line, a second line, a first connecting line, a second connecting line, a third relay 7, and a fourth relay 8; each first cell 3 has a corresponding first connecting line connected to its positive terminal, with one end of each first connecting line connected to the positive terminal of the corresponding first cell 3 and the other end connected to the first line; each first cell 3 has a corresponding second connecting line connected to its negative terminal, with one end of each second connecting line connected to the negative terminal of the corresponding first cell 3 and the other end connected to the second line; each first connecting line has a third relay 7, and each second connecting line has a fourth relay 8. The second parallel sub-circuit includes a third line, a fourth line, a third connecting line, a fourth connecting line, a fifth relay 9, and a sixth relay 10; each second cell 4 has a corresponding third connecting line connected to its positive terminal, with one end of each third connecting line connected to the positive terminal of the corresponding second cell 4 and the other end connected to the third line; each second cell 4 has a corresponding fourth connecting line connected to its negative terminal, with one end of each fourth connecting line connected to the negative terminal of the corresponding second cell 4 and the other end connected to the fourth line; each third connecting line has a fifth relay 9, and each fourth connecting line has a sixth relay 10.

[0034] The power battery provided in Example 1 has a specific structure in which the ratio between the high-voltage platform (i.e., the voltage of the power battery when switching to the second circuit structure) and the low-voltage platform (i.e., the voltage of the power battery when switching to the first circuit structure) is at least three times. This allows the power battery to switch between the first circuit structure and the second circuit structure by adjusting the on / off states of each of the first relays 5, second relays, third relays 7, fourth relays 8, fifth relays 9, and sixth relays 10. Furthermore, it enables the isolation of the faulty cell when any of the first cells 3 or second cells 4 fails, by switching to the first circuit structure and controlling each of the fourth relays 8 or fifth relays 9. The faulty first cell 3 or second cell 4 (for example, but not limited to: controlling the second relay 6 connected to the second series line between the non-faulty first cell 3 and the non-faulty second cell 4 to close, and controlling the second relay 6 connected to the second series line of the faulty first cell 3 or second cell 4 to open; then controlling the fourth relay 8 on the second connection line corresponding to the faulty first cell 3 to open, or controlling the fifth relay 9 on the third connection line corresponding to the faulty second cell 4 to open) can ensure that the power battery can operate stably in low voltage platform mode while isolating the faulty first cell 3 or second cell 4 and losing only the capacity of one cell.

[0035] Example 2: Based on the power battery provided in Embodiment 1, Embodiment 2 also provides a power battery. The structure of the power battery provided in Embodiment 2 is similar to that of the power battery provided in Embodiment 1, except that: In this embodiment 2, as Figure 2 As shown, the power battery includes two battery modules; the first parallel sub-circuit includes a fifth line, a sixth line, a seventh relay 11, and an eighth relay 12; One end of the fifth line is connected to the positive terminal of one of the first cells 3, and the other end of the fifth line is connected to the positive terminal of the other first cell 3; one end of the sixth line is connected to the negative terminal of one of the first cells 3, and the other end of the sixth line is connected to the negative terminal of the other first cell 3. The seventh relay 11 is installed on the fifth line, and the eighth relay 12 is installed on the sixth line; The second parallel sub-circuit includes the seventh line, the eighth line, the ninth relay 13, and the tenth relay 14; One end of the seventh line is connected to the positive terminal of one of the second cells 4, and the other end of the seventh line is connected to the positive terminal of the other second cell 4; one end of the eighth line is connected to the negative terminal of one of the second cells 4, and the other end of the eighth line is connected to the negative terminal of the other second cell 4. The ninth relay 13 is installed on the seventh line, and the tenth relay 14 is installed on the eighth line.

[0036] The power battery provided in Example 2 exhibits a specific structure with a voltage ratio of twice that between the high-voltage platform (i.e., the voltage of the power battery when switching to the second circuit structure) and the low-voltage platform (i.e., the voltage of the power battery when switching to the first circuit structure). This allows the power battery to switch between the first and second circuit structures by adjusting the on / off states of each of the first relays 5, each of the second electrical components, the seventh relay 11, the eighth relay 12, the ninth relay 13, and the tenth relay 14. Furthermore, it enables the power battery to switch between the first and second circuit structures when any of the first cells 3 or any of the second cells 4 fails, by switching to the first circuit structure and controlling the eighth relay 12 or the ninth relay. 13 can isolate the faulty first cell 3 or second cell 4 (for example, but not limited to: controlling the second relay 6 connected to the second series line between the non-faulty first cell 3 and the non-faulty second cell 4 to close, and controlling the second relay 6 connected to the second series line of the faulty first cell 3 or second cell 4 to open; when the first cell 3 fails, controlling the eighth relay 12 to open, and when the second cell 4 fails, controlling the ninth relay 13 to open), thus ensuring that the power battery can operate stably in low voltage platform mode while isolating the faulty first cell 3 or second cell 4 and losing only the capacity of one cell.

[0037] Example 3: Based on the power batteries provided in Embodiments 1 and 2, Embodiment 3 provides a series-parallel control method for a power battery, the series-parallel control method including: Obtain high-voltage platform mode information or low-voltage platform mode information; Based on the obtained low-voltage platform mode information, the control switching circuit switches the connection mode between the multiple first cells 3 and multiple second cells 4 contained in the power battery to obtain the first circuit structure. Based on the obtained high-voltage platform mode information, the control switching circuit switches the connection mode between the multiple first cells 3 and multiple second cells 4 contained in the power battery to obtain the second circuit structure.

[0038] Among them, such as Figure 3 and Figure 4 As shown, the method for obtaining the first circuit structure includes: All first relays 5 of the control switching circuit are disconnected, one of the second relays 6 of the control switching circuit is closed, and the remaining second relays 6 of the control switching circuit are disconnected. The first parallel sub-circuit of the control switching circuit connects all the first cells 3 in parallel, and the second parallel sub-circuit of the control switching circuit connects all the second cells 4 in parallel.

[0039] Among them, such as Figure 5 and Figure 6 As shown, the method for obtaining the second circuit structure includes: The first parallel sub-circuit of the control switching circuit disconnects and connects all the first cells 3 in parallel, and the second parallel sub-circuit of the control switching circuit disconnects and connects all the second cells 4 in parallel. All first relays 5 and all second relays 6 of the control switching circuit are closed.

[0040] It should be noted that, in Figure 3 , Figure 4 , Figure 5 and Figure 6 In order to make the circuit structure clearer, the circuits containing disconnected relays have been hidden, and all relays not shown are assumed to be in the disconnected state.

[0041] Specifically, in this embodiment 3, as Figure 3 As shown, based on the power battery provided in Embodiment 1, the method for controlling the first parallel sub-circuit to connect all the first cells 3 in parallel includes: All third relays 7 and all fourth relays 8 controlling the first parallel sub-circuit are closed; The methods for controlling the second parallel sub-circuit to connect all the second cells 4 in parallel include: All fifth relays 9 and all sixth relays 10 controlling the second parallel sub-circuit are closed.

[0042] Specifically, in this embodiment 3, as Figure 4As shown, based on the power battery provided in Embodiment 2, the method for controlling the first parallel sub-circuit to connect all the first cells 3 in parallel includes: Both the seventh relay 11 and the eighth relay 12, which control the first parallel sub-circuit, are closed.

[0043] The methods for controlling the second parallel sub-circuit to connect all the second cells 4 in parallel include: The ninth relay 13 and the tenth relay 14, which control the second parallel sub-circuit, are both closed.

[0044] Specifically, in this embodiment 3, as Figure 5 As shown, based on the power battery provided in Embodiment 1, the method for controlling the first parallel sub-circuit to disconnect and connect all the first cells 3 in parallel includes: All third relays 7 and all fourth relays 8 controlling the first parallel sub-circuit are disconnected; Methods for controlling the second parallel sub-circuit to disconnect and connect all second cells 4 in parallel include: All fifth relays 9 and all sixth relays 10 controlling the second parallel sub-circuit are disconnected.

[0045] Specifically, in this embodiment 3, as Figure 6 As shown, based on the power battery provided in Embodiment 2, the method for controlling the first parallel sub-circuit to disconnect and connect all the first cells 3 in parallel includes: The seventh relay 11 and the eighth relay 12, which control the first parallel sub-circuit, are both disconnected.

[0046] Methods for controlling the second parallel sub-circuit to disconnect and connect all second cells 4 in parallel include: The ninth relay 13 and the tenth relay 14, which control the second parallel sub-circuit, are both disconnected.

[0047] Example 4: Based on the power battery provided in Example 1, Example 4 provides a fault control method for the power battery, the fault control method comprising: Obtain first fault information of any first cell 3 of the power battery failing, or second fault information of any second cell 4 failing; Based on the obtained first fault information or second fault information, the control switching circuit switches the connection mode between the multiple first cells 3 and multiple second cells 4 contained in the power battery to obtain the first circuit structure; Then, based on the obtained first fault information, control the fourth relay 8 on the second connection line corresponding to the faulty first battery cell 3 to disconnect, or control the fifth relay 9 on the third connection line corresponding to the faulty second battery cell 4 to disconnect. The method for obtaining the first circuit structure is as follows: all first relays 5 of the control switching circuit are disconnected; any second relay 6 connected in the second series line between the first battery cell 3 and the second battery cell 4 that has not failed is closed; and the remaining second relays 6 are disconnected; then all third relays 7 and all fourth relays 8 of the first parallel sub-circuit of the control switching circuit, as well as all fifth relays 9 and all sixth relays 10 of the second parallel sub-circuit of the control switching circuit, are closed.

[0048] Figure 7 and Figure 8 Two examples are given respectively regarding the final circuit structure of the power battery obtained according to the fault control method provided in Example 4. Figure 7 In the given example, the first cell 3 of the first battery assembly failed; in Figure 8 In the example given, the second cell 4 of the first battery assembly failed.

[0049] It should be noted that, in Figure 7 and Figure 8 In order to make the circuit structure clearer, most of the circuits containing disconnected relays have been hidden, and all relays not shown are assumed to be in the disconnected state.

[0050] Example 5: Based on the power battery provided in Example 2, Example 5 provides a fault control method for the power battery, the fault control method including: Obtain first fault information of any first cell 3 of the power battery failing, or second fault information of any second cell 4 failing; Based on the obtained first fault information or second fault information, the control switching circuit switches the connection mode between the multiple first cells 3 and multiple second cells 4 contained in the power battery to obtain the first circuit structure; Then, based on the first fault information obtained, the eighth relay 12 of the first parallel sub-circuit of the control switching circuit is disconnected, or based on the second fault information obtained, the ninth relay 13 of the second parallel sub-circuit of the control switching circuit is disconnected. The method for obtaining the first circuit structure is as follows: all first relays 5 of the control switching circuit are disconnected; the second relay 6 connected in the second series line between the first battery cell 3 and the second battery cell 4 that has not failed is closed; and another second relay 6 is disconnected; the seventh relay 11 and the eighth relay 12 of the first parallel sub-circuit of the control switching circuit, as well as the ninth relay 13 and the tenth relay 14 of the second parallel sub-circuit of the control switching circuit are all closed.

[0051] Figure 9 and Figure 10 Two examples are given respectively regarding the final circuit structure of the power battery obtained according to the fault control method provided in Example 5. Figure 9 In the given example, the first cell 3 of the second battery assembly failed; Figure 10 In the example given, the second cell 4 of the second battery assembly failed.

[0052] It should be noted that, in Figure 9 and Figure 10 In order to make the circuit structure clearer, most of the circuits containing disconnected relays have been hidden, and all relays not shown are assumed to be in the disconnected state.

[0053] Example 6: Based on the power battery provided in Example 2, Example 6 provides a fault control method for the power battery, the fault control method including: Obtain first fault information of any first cell 3 of the power battery failing, or second fault information of any second cell 4 failing; Based on the obtained first or second fault information, the first relay 5 of the control switching circuit is opened, the second relay 6 connected in the second series line between the first battery cell 3 and the second battery cell 4 that has not experienced a fault is closed, and the other second relay 6 is opened; the eighth relay 12 of the first parallel sub-circuit of the control switching circuit and the ninth relay 13 of the second parallel sub-circuit of the control switching circuit are both opened, and the seventh relay 11 of the first parallel sub-circuit and the tenth relay 14 of the second parallel sub-circuit are both closed.

[0054] Figure 11 An example is given of the final circuit structure of the power battery obtained according to the fault control method provided in Example 6. Figure 11 In the example given, the second cell 4 of the second battery assembly failed.

[0055] It should be noted that, in Figure 11 In order to make the circuit structure clearer, most of the circuits containing disconnected relays have been hidden, and all relays not shown are assumed to be in the disconnected state.

[0056] By disconnecting the first relay 5 and closing the second relay 6 on the second series circuit between the first cell 3 and the second cell 4 that have not failed, and then disconnecting the other second relay 6, followed by disconnecting the eighth relay 12 and the ninth relay 13, and closing the seventh relay 11 and the tenth relay 14, only one first cell 3 and one second cell 4 that have not failed are connected in series sequentially between the positive circuit 1 and the negative circuit 2 of the power battery. Although this will cause the power battery to isolate the first cell 3 or the second cell 4 that has not failed in the same battery pack when isolating the first cell 3 or the second cell 4 that has failed, resulting in a loss of capacity of two cells, it can also avoid the problem of uneven distribution of charging and discharging current caused by the difference in consistency of the cells when there are two cells in parallel and then one cell in series between the positive circuit 1 and the negative circuit 2, which would affect the cell life and the reliability of the power battery.

[0057] The power battery, the series-parallel control method for the power battery, and the fault control method provided by this invention have at least the following technical effects or advantages: 1. By setting a switching circuit to switch the connection mode between the multiple first cells 3 and multiple second cells 4 contained in the power battery, a first circuit structure or a second circuit structure is obtained; this enables the power battery provided by the present invention to switch between a high-voltage platform (i.e., when switching to the second circuit structure) and a low-voltage platform (i.e., when switching to the first circuit structure), so that electric vehicles using the power battery provided by the present invention can be compatible with both supercharging piles and low-voltage charging piles, and can also be compatible with the supply chain of existing low-voltage platform models during vehicle development; during charging, it can take into account the high efficiency of high-voltage charging and the charging convenience of low-voltage charging, and can also help developers balance performance and modification costs during vehicle development, solving the technical problem that current high-voltage platform models still have shortcomings in the balance between charging convenience, performance and development costs.

[0058] 2. The power battery provided by this invention can adjust the ratio between the high-voltage platform (i.e., the voltage of the power battery when switching to the second circuit structure) and the low-voltage platform (i.e., the voltage of the power battery when switching to the first circuit structure) by adjusting the number of battery components during the development process. This allows the power battery provided by this invention to be free from the current limitation of high-voltage platform development being mostly limited to the 800V voltage level, and has a great degree of development freedom. It can adapt to the future development direction of high-voltage platforms to above 800V, and can better adapt to the future development direction of the industry.

[0059] 3. The power battery provided in Example 1 provides a specific structure in which the ratio between the high-voltage platform (i.e., the voltage of the power battery when switching to the second circuit structure) and the low-voltage platform (i.e., the voltage of the power battery when switching to the first circuit structure) is at least three times. This allows the power battery to switch between the first circuit structure and the second circuit structure by adjusting the on / off states of each first relay 5, each second relay, each third relay 7, each fourth relay 8, each fifth relay 9, and each sixth relay 10. Furthermore, it enables the isolation of the power battery when any first cell 3 or any second cell 4 fails, by switching to the first circuit structure and controlling each fourth relay 8 or each fifth relay 9. The faulty first cell 3 or second cell 4 (for example, but not limited to: controlling the second relay 6 connected to any of the second series lines between the non-faulty first cell 3 and the non-faulty second cell 4 to close, and controlling the second relay 6 connected to the second series line of the faulty first cell 3 or second cell 4 to open; then controlling the fourth relay 8 on the second connection line corresponding to the faulty first cell 3 to open, or controlling the fifth relay 9 on the third connection line corresponding to the faulty second cell 4 to open) can ensure that the power battery can operate stably in low-voltage platform mode while isolating the faulty first cell 3 or second cell 4 and losing only the capacity of one cell.

[0060] 4. The power battery provided in Example 2 provides a specific structure for a power battery with a voltage ratio of twice that between a high-voltage platform (i.e., the voltage of the power battery when switching to the second circuit structure) and a low-voltage platform (i.e., the voltage of the power battery when switching to the first circuit structure). This allows the power battery to switch between the first circuit structure and the second circuit structure by adjusting the on / off states of each of the first relays 5, each of the second electrical components, the seventh relay 11, the eighth relay 12, the ninth relay 13, and the tenth relay 14. Furthermore, it enables the power battery to switch between the first circuit structure and the second circuit structure when any of the first cells 3 or any of the second cells 4 fails, by switching to the first circuit structure and controlling the eighth relay 12 or the ninth relay 14. Device 13 isolates the faulty first cell 3 or second cell 4 (for example, but not limited to: controlling the second relay 6 connected to the second series line between the non-faulty first cell 3 and the non-faulty second cell 4 to close, and controlling the second relay 6 connected to the second series line of the faulty first cell 3 or second cell 4 to open; when the first cell 3 fails, controlling the eighth relay 12 to open, and when the second cell 4 fails, controlling the ninth relay 13 to open), thus ensuring that the power battery can operate stably in low-voltage platform mode while isolating the faulty first cell 3 or second cell 4 and losing only the capacity of one cell.

[0061] 5. By disconnecting the first relay 5 and closing the second relay 6 on the second series circuit between the first cell 3 and the second cell 4 that have not failed, and then disconnecting the other second relay 6, and then disconnecting the eighth relay 12 and the ninth relay 13, and closing the seventh relay 11 and the tenth relay 14, only one first cell 3 and one second cell 4 that have not failed are connected in series in sequence between the positive circuit 1 and the negative circuit 2 of the power battery. Although this will cause the power battery to isolate the first cell 3 or the second cell 4 that has not failed in the same battery pack when isolating the first cell 3 or the second cell 4 that has failed, resulting in a loss of capacity of two cells, it can also avoid the problem of uneven distribution of charging and discharging current caused by the difference in consistency of cells when two cells are connected in parallel and then one cell is connected in series between the positive circuit 1 and the negative circuit 2, which will affect the cell life and reliability of the power battery.

[0062] The above are merely specific application examples of the present invention and do not constitute any limitation on the scope of protection of the present invention. All technical solutions formed by equivalent transformation or equivalent substitution fall within the scope of protection of the present invention.

Claims

1. A power cell, characterized by: The power battery comprises a positive electrode circuit, a negative electrode circuit, a switching circuit and a plurality of battery assemblies; each of the battery assemblies comprises a first cell and a second cell; all of the first cells and all of the second cells comprised by the power battery are connected with the switching circuit; The plurality of battery assemblies are arranged in sequence, the positive electrode circuit is connected with the positive electrode of the first cell of the first battery assembly, and the negative electrode circuit is connected with the negative electrode of the second cell of the last battery assembly; The switching circuit is used for switching the connection mode between the plurality of first cells and the plurality of second cells comprised by the power battery, so as to obtain a first circuit structure or a second circuit structure; The first circuit structure comprises a first battery unit and a second battery unit, the first battery unit is composed of all of the first cells comprised by the power battery and connected in parallel, the second battery unit is composed of all of the second cells comprised by the power battery and connected in parallel, and the negative electrode of the first battery unit is connected with the positive electrode of the second battery unit; The second circuit structure comprises all of the battery assemblies comprised by the power battery connected in series in sequence according to the arrangement order, and the negative electrode of the first cell of any battery assembly is connected with the positive electrode of the second cell of the battery assembly, and in two adjacent battery assemblies, the negative electrode of the second cell of the former battery assembly is connected with the positive electrode of the first cell of the latter battery assembly.

2. The power cell of claim 1, wherein: The switching circuit comprises a first parallel sub-circuit, a second parallel sub-circuit, a first series circuit, a second series circuit, a first relay and a second relay; All of the first cells are connected with the first parallel sub-circuit, and the first parallel sub-circuit is used for connecting all of the first cells in parallel or disconnecting the parallel connection of all of the first cells; All of the second cells are connected with the second parallel sub-circuit, and the second parallel sub-circuit is used for connecting all of the second cells in parallel or disconnecting the parallel connection of all of the second cells; In any two adjacent battery assemblies, the negative electrode of the second cell of the former battery assembly and the positive electrode of the first cell of the latter battery assembly are connected with a first series circuit, and the negative electrode of the first cell and the positive electrode of the second cell of each battery assembly are connected with a second series circuit; each first series circuit is provided with a first relay, and each second series circuit is provided with a second relay.

3. The power cell of claim 2, wherein: The power battery comprises at least three battery assemblies; the first parallel sub-circuit comprises a first line, a second line, a first connecting line, a second connecting line, a third relay and a fourth relay; one first connecting line is connected to the positive pole of each first battery cell, one end of each first connecting line is connected to the positive pole of the corresponding first battery cell, and the other end of each first connecting line is connected to the first line; one second connecting line is connected to the negative pole of each first battery cell, one end of each second connecting line is connected to the negative pole of the corresponding first battery cell, and the other end of each second connecting line is connected to the second line; one third relay is arranged on each first connecting line, and one fourth relay is arranged on each second connecting line; The second parallel sub-circuit comprises a third line, a fourth line, a third connecting line, a fourth connecting line, a fifth relay and a sixth relay; one third connecting line is connected to the positive pole of each second battery cell, one end of each third connecting line is connected to the positive pole of the corresponding second battery cell, and the other end of each third connecting line is connected to the third line; one fourth connecting line is connected to the negative pole of each second battery cell, one end of each fourth connecting line is connected to the negative pole of the corresponding second battery cell, and the other end of each fourth connecting line is connected to the fourth line; one fifth relay is arranged on each third connecting line, and one sixth relay is arranged on each fourth connecting line.

4. The power cell of claim 2, wherein: The power battery comprises two battery assemblies; the first parallel sub-circuit comprises a fifth line, a sixth line, a seventh relay and an eighth relay; One end of the fifth line is connected to the positive pole of one of the first battery cells, and the other end of the fifth line is connected to the positive pole of the other first battery cell; one end of the sixth line is connected to the negative pole of one of the first battery cells, and the other end of the sixth line is connected to the negative pole of the other first battery cell; The seventh relay is arranged on the fifth line, and the eighth relay is arranged on the sixth line; The second parallel sub-circuit comprises a seventh line, an eighth line, a ninth relay and a tenth relay; One end of the seventh line is connected to the positive pole of one of the second battery cells, and the other end of the seventh line is connected to the positive pole of the other second battery cell; one end of the eighth line is connected to the negative pole of one of the second battery cells, and the other end of the eighth line is connected to the negative pole of the other second battery cell; The ninth relay is arranged on the seventh line, and the tenth relay is arranged on the eighth line.

5. The method for controlling series-parallel connection of power batteries according to any one of claims 1-4, characterized in that, The series-parallel control method comprises: obtaining high-voltage platform mode information or low-voltage platform mode information; controlling a switching circuit to switch the communication mode between a plurality of first battery cells and a plurality of second battery cells included in the power battery according to the obtained low-voltage platform mode information, to obtain a first circuit structure; According to the obtained high-voltage platform mode information, the switching circuit is controlled to switch the connection mode between the plurality of first battery cells and the plurality of second battery cells contained in the power battery, so as to obtain a second circuit structure.

6. The method according to claim 5, wherein: The method for obtaining the first circuit structure comprises: all the first relays of the switching circuit are controlled to be disconnected, one of the second relays of the switching circuit is controlled to be closed, and the remaining second relays of the switching circuit are controlled to be disconnected; the first parallel sub-circuit of the switching circuit is controlled to connect all the first battery cells in parallel, and the second parallel sub-circuit of the switching circuit is controlled to connect all the second battery cells in parallel.

7. The method according to claim 5, wherein: The method for obtaining the second circuit structure comprises: the first parallel sub-circuit of the switching circuit is controlled to disconnect all the first battery cells in parallel, and the second parallel sub-circuit of the switching circuit is controlled to disconnect all the second battery cells in parallel; all the first relays and all the second relays of the switching circuit are controlled to be closed.

8. A method for failure control of a power cell as defined in claim 3, characterized by The fault control method comprises: first fault information of any first battery cell of the power battery or second fault information of any second battery cell of the power battery is obtained; according to the obtained first fault information or second fault information, the switching circuit is controlled to switch the connection mode between the plurality of first battery cells and the plurality of second battery cells contained in the power battery, so as to obtain a first circuit structure; further according to the obtained first fault information, a fourth relay on a second connection line corresponding to the first battery cell that has failed is controlled to be disconnected, or further according to the obtained second fault information, a fifth relay on a third connection line corresponding to the second battery cell that has failed is controlled to be disconnected; The method for obtaining the first circuit structure comprises: all the first relays of the switching circuit are controlled to be disconnected, one of the second relays of the switching circuit is controlled to be closed, and the remaining second relays of the switching circuit are controlled to be disconnected; all the third relays and all the fourth relays of the first parallel sub-circuit of the switching circuit and all the fifth relays and all the sixth relays of the second parallel sub-circuit of the switching circuit are controlled to be closed.

9. A method for failure control of a power cell as defined in claim 4, characterized by The fault control method comprises: first fault information of any first battery cell of the power battery or second fault information of any second battery cell of the power battery is obtained; according to the obtained first fault information or second fault information, the switching circuit is controlled to switch the connection mode between the plurality of first battery cells and the plurality of second battery cells contained in the power battery, so as to obtain a first circuit structure; further according to the obtained first fault information, an eighth relay of the first parallel sub-circuit of the switching circuit is controlled to be disconnected, or further according to the obtained second fault information, a ninth relay of the second parallel sub-circuit of the switching circuit is controlled to be disconnected; The method for obtaining the first circuit structure is: controlling all the first relays of the switching circuit to be disconnected, controlling a second relay connected to a second series circuit between the first battery cell without failure and the second battery cell without failure to be closed, and controlling another second relay to be disconnected; controlling the seventh relay and the eighth relay of the first parallel sub-circuit of the switching circuit and the ninth relay and the tenth relay of the second parallel sub-circuit of the switching circuit to be closed.

10. A method of failure control of a power cell as defined in claim 4, characterized by The fault control method comprises: obtaining first fault information of any first battery cell of the power battery or second fault information of any second battery cell; controlling the first relay of the switching circuit to be disconnected, controlling a second relay connected to a second series circuit between the first battery cell without failure and the second battery cell without failure to be closed, and controlling another second relay to be disconnected; controlling the eighth relay of the first parallel sub-circuit of the switching circuit and the ninth relay of the second parallel sub-circuit of the switching circuit to be disconnected, and controlling the seventh relay of the first parallel sub-circuit and the tenth relay of the second parallel sub-circuit to be closed.

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