Battery system for low-voltage power supply of vehicle through DCDC module and vehicle

Abstract

The invention belongs to the technical field of low-voltage power supply of new energy vehicles, and particularly relates to a battery system for low-voltage power supply of a vehicle through a DCDC module and the vehicle. Ni DCDC modules are arranged in the ith battery pack of the battery system, Ni is larger than or equal to 1, i is equal to 1, 2,..., K, and K represents the total number of the battery packs; all battery cells in the battery pack with Ni = 1 are connected in series and then connected with the high-voltage end of the DCDC module; the battery cells in the battery pack with Ni greater than or equal to 2 are divided into N groups, the battery cells in one group are connected in series and then are connected with the high-voltage end of one DCDC module, and the battery cells in different groups are connected with the high-voltage ends of different DCDC modules; the low-voltage ends of the DCDC modules are connected in parallel and then used for outputting low-voltage electricity so as to supply power to a vehicle low-voltage system. In addition, the DCDC module is protected by directly using the battery pack and the shell of the battery system, and a protection structure of the DCDC module does not need to be additionally arranged, so that the cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of low-voltage power supply for new energy vehicles, and in particular relates to a battery system and a vehicle for performing low-voltage power supply for a vehicle through a DCDC module. Background Art

[0002] At present, new energy vehicles generally use lead-acid batteries to power the low-voltage devices of the whole vehicle. The DCDC outside the battery pack converts the high voltage of the power battery into low voltage to charge the lead-acid battery. The lead-acid battery plays an important function such as powering the whole vehicle. Since the life and energy density of lead-acid batteries are not advantageous, some high-end vehicles switch to lithium-ion batteries with more advantageous life and energy density. Lithium-ion batteries have a long cycle life. Lead-acid batteries need to be replaced once during the life cycle of the whole vehicle. Lithium-ion batteries can meet the use needs of the whole life cycle of the whole vehicle. Lithium-ion batteries have a high energy density and weigh about 30% of lead-acid batteries. However, the cost of lithium-ion batteries is relatively high, which is twice that of lead-acid batteries (the cost is calculated based on replacement once during the life cycle of the whole vehicle). The whole vehicle urgently needs a low-voltage power supply solution with more advantages in weight and cost than lead-acid batteries and lithium-ion batteries.

[0003] In order to solve the above technical problems, the Chinese invention patent application with application publication number CN118082506A proposed a technical solution to realize low-voltage power supply by converting the high-voltage electricity of the power battery into low-voltage electricity through a power management module and a DCDC module. However, to output low-voltage electricity from the power battery through the DCDC module, not only a contactor is required to control the power supply line, but also a protection structure such as leakage protection and waterproof protection is required for the power supply line, which will occupy a certain amount of vehicle space and also lead to an increase in cost. Summary of the invention

[0004] The object of the present invention is to provide a battery system and a vehicle for supplying low voltage to a vehicle through a DCDC module, so as to solve the technical problem that when a power battery supplies low voltage to a vehicle through a DCDC module, a contactor and a protection structure occupy vehicle space and cause an increase in vehicle cost.

[0005] In order to solve the above technical problems, the present invention provides a battery system for low-voltage power supply of a vehicle through a DCDC module, wherein the i-th battery pack of the battery system is provided with Ni DCDC modules, Ni≥1, i=1,2,……,K, K represents the total number of battery packs;

[0006] All cells in a battery pack with Ni=1 are connected in series to the high-voltage end of the DCDC module; cells in a battery pack with Ni≥2 are divided into N groups, and cells in one group are connected in series to the high-voltage end of a DCDC module, and cells in different groups are connected to the high-voltage ends of different DCDC modules;

[0007] The low-voltage ends of the DCDC modules are connected in parallel to output low-voltage electricity to supply power to the vehicle's low-voltage system.

[0008] Furthermore, the main circuit of each DCDC module is in a conducting state after the battery system is assembled on the vehicle, and the low-voltage ends of each DCDC module are connected in parallel and output through the anti-reverse module, and the output voltage of the low-voltage ends of the DCDC modules after being connected in parallel is lower than the voltage of the DCDC output of the whole vehicle, so that the vehicle's low-voltage system gives priority to using the power output of the DCDC of the whole vehicle when the whole vehicle is powered on.

[0009] Furthermore, the low-level activation pins of each DCDC module are used to connect to the vehicle body when the battery system is assembled on the vehicle, and are in a floating state when the battery system is not assembled on the vehicle; the DCDC module is used to disconnect the main circuit inside it when its low-level activation pin is in a floating state, and to turn on the main circuit inside it when the low-level activation pin is grounded through the vehicle body to ensure that the main circuits are in a conducting state after the battery system is assembled on the vehicle.

[0010] Furthermore, the high-level activation pin of each DCDC module is used to connect to the low-voltage charging circuit of the charging gun or the DCDC activation source, so as to start the DCDC module after receiving a high-level signal when the DCDC module is in the shutdown state.

[0011] Furthermore, the number of cells in each group in the same battery pack is equal.

[0012] Furthermore, the communication pin of the DCDC module is also used to connect to the vehicle battery management system to receive a shutdown command issued by the battery management system and enter a shutdown state when the battery pack is under-voltage.

[0013] The present invention is an improved invention creation, and its beneficial effects are as follows: the battery system of the present invention that uses a DCDC module to supply low-voltage power to the vehicle saves vehicle space by setting the DCDC inside the battery pack, and the DCDC module is directly protected by the outer shell of the battery pack and the battery system, and there is no need to set up an additional protection structure for the DCDC module, thereby reducing costs. At the same time, since the battery system includes multiple battery packs, each battery pack includes a DCDC module, and multiple DCDC modules are connected in parallel to supply power to the low-voltage system of the vehicle, when one DCDC module is damaged, the other DCDC modules can still supply power normally, thereby enhancing the reliability of using DCDC modules to replace batteries. The number of DCDC modules in a battery pack can also be set to two or more DCDC modules according to the capacity of the battery pack, and a certain number of cells are connected to the high-voltage end of each DCDC module. The reliability of the ground voltage power supply of the battery system is further improved.

[0014] In order to solve the above technical problems, the present invention further provides a vehicle that uses a DCDC module to supply low voltage to the vehicle, wherein the i-th battery pack of the battery system of the vehicle is provided with Ni DCDC modules, Ni≥1, i=1,2,……,K, K represents the total number of battery packs;

[0015] All cells in a battery pack with Ni=1 are connected in series to the high-voltage end of the DCDC module; cells in a battery pack with Ni≥2 are divided into N groups, and cells in one group are connected in series to the high-voltage end of a DCDC module, and cells in different groups are connected to the high-voltage ends of different DCDC modules;

[0016] The low-voltage ends of the DCDC modules are connected in parallel to output low-voltage electricity to supply power to the vehicle's low-voltage system.

[0017] Furthermore, the main circuit of each DCDC module is in a conducting state after the battery system is assembled on the vehicle, and the low-voltage ends of each DCDC module are connected in parallel and output through the anti-reverse module, and the output voltage of the low-voltage ends of the DCDC modules after being connected in parallel is lower than the voltage of the DCDC output of the whole vehicle, so that the vehicle's low-voltage system gives priority to using the power output of the DCDC of the whole vehicle when the whole vehicle is powered on.

[0018] Furthermore, the low-level activation pins of each DCDC module are used to connect to the vehicle body when the battery system is assembled on the vehicle, and are in a floating state when the battery system is not assembled on the vehicle; the DCDC module is used to disconnect the main circuit inside it when its low-level activation pin is in a floating state, and to turn on the main circuit inside it when the low-level activation pin is grounded through the vehicle body to ensure that the main circuits are in a conducting state after the battery system is assembled on the vehicle.

[0019] Furthermore, the high-level activation pin of each DCDC module is used to connect to the low-voltage charging circuit of the charging gun or the DCDC activation source, so as to start the DCDC module after receiving a high-level signal when the DCDC module is in the shutdown state.

[0020] Furthermore, the number of cells in each group in the same battery pack is equal.

[0021] Furthermore, the communication pin of the DCDC module is also used to connect to the vehicle battery management system to receive a shutdown command issued by the battery management system and enter a shutdown state when the battery pack is under-voltage.

[0022] The present invention is an improved invention, and its beneficial effects are the same as those of the battery system of the present invention that realizes low-voltage power supply through DCDC. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 1 is a structural diagram of a battery system according to an embodiment of the battery system of the present invention. DETAILED DESCRIPTION

[0024] The present invention discloses a battery system and a vehicle that uses a DCDC module to supply low voltage power to a vehicle. The battery system that uses a DCDC module to supply low voltage power to a vehicle saves vehicle space by setting the DCDC inside the battery pack, and the DCDC module directly uses the outer shell of the battery pack and the battery system for protection, and does not need to additionally set up a protective structure of the DCDC module, thereby reducing costs. At the same time, since the battery system includes multiple battery packs, each battery pack includes a DCDC module, and multiple DCDC modules are connected in parallel to supply power to the low voltage system of the vehicle, when one DCDC module is damaged, the other DCDC modules can still supply power normally, thereby enhancing the reliability of using the DCDC module to replace the battery. The number of DCDC modules in a battery pack can also be set to two or more DCDC modules according to the capacity of the battery pack, and a certain number of battery cells are connected to the high voltage end of each DCDC module. The reliability of the ground voltage power supply of the battery system is further improved.

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0026] Battery system example:

[0027] The battery system of the present invention is provided with Ni DCDC modules in the i-th battery pack of the battery system, Ni≥1, i=1,2,……,K, K represents the total number of battery packs; all the cells in the battery pack of Ni=1 are connected in series to the high-voltage end of the DCDC module; the cells in the battery pack of Ni≥2 are divided into N groups, the cells in one group are connected in series to the high-voltage end of a DCDC module, and different groups of cells are connected to the high-voltage ends of different DCDC modules; the low-voltage ends of each DCDC module are connected in parallel to output low-voltage electricity to supply power to the low-voltage system of the vehicle. By setting the DCDC inside the battery pack, the vehicle space is saved, and the DCDC module is directly protected by the outer shell of the battery pack and the battery system, and there is no need to set up an additional protection structure of the DCDC module, which reduces the cost. At the same time, since the battery system includes multiple battery packs, each battery pack includes a DCDC module, and the low-voltage system of the vehicle is supplied with power after multiple DCDC modules are connected in parallel, when one DCDC module is damaged, the other DCDC modules can still supply power normally, which enhances the reliability of using the DCDC module to replace the battery as the low-voltage starting power supply of the vehicle.

[0028] The number of DCDC modules in a single battery pack can be set according to the capacity of the battery pack. For a commercial vehicle battery system with a large single battery pack capacity, two or more DCDC modules (hereinafter referred to as DCDC) can be set in the battery pack. In this embodiment, two DCDCs are set in each battery pack as an example for explanation. In this embodiment, the number of cells in each group in the same battery pack is equal, that is, the number of cells connected to each DCDC is equal. As other implementations, the number of DCDC modules in different battery packs can also be different, and the number of cells connected to different DCDC modules in the same battery pack can also be different.

[0029] In this embodiment, the structure of the battery system is as follows: Figure 1 As shown, each battery pack includes two DCDCs, and the high-voltage ends (H+ and H-) of the two DCDCs are respectively connected to the two ends of a set number of cells in the battery pack. In order to avoid a large consistency difference in a single cell in the battery pack, the number of cells connected to the high-voltage ends of each DCDC in the same battery pack is the same. Therefore, in this embodiment, each DCDC is connected to half of the cells in the battery pack, and the low-voltage ends (L+ and L-) of the DCDC are connected to their respective DCDC interfaces ( Figure 1 In ①~⑥), each DCDC interface is connected in parallel to provide low voltage power to the vehicle. As another implementation, the low voltage end of the DCDC can be directly connected in parallel to supply power to the low voltage system of the vehicle without using the DCDC interface.

[0030] In this embodiment, the battery system is used as a vehicle starting power supply to supply power to the vehicle low-voltage system when the vehicle is not powered on. Since the battery system of the present invention is used to replace the battery, when the battery system of the present invention is configured on the vehicle, it is necessary to use it as a starting power supply to supply power to the vehicle low-voltage system when the vehicle is not powered on. In order to ensure this effect, one solution is that the DCDC main circuit is always turned on, and as long as the battery system is configured on the vehicle, low-voltage electricity is output to the outside to supply power to the vehicle low-voltage system. However, in this solution, when the battery system is not configured on the vehicle, for example, when stored in a warehouse, although the DCDC main circuit is not connected to the load, since the DCDC main circuit is turned on and is in a light-load state, the DCDC will continue to consume the battery pack power. Being in this state for a long time may cause the battery pack to lose points and consistency differences to be large, affecting the normal use of the battery system.

[0031] In order to solve this problem, the present invention proposes another solution. When the battery system is not configured on the vehicle, the DCDC main circuit is not turned on to avoid the low power consumption of the light load mode and the continuous consumption of the battery pack power. Furthermore, in order to realize that the DCDC starts working immediately after the battery system is configured on the vehicle, the low level activation pin ( Figure 1Medium activation (low) is used to connect the vehicle body when the battery system is installed on the vehicle, and is left floating when the battery system is not installed on the vehicle; the DCDC module is used to control the main circuit of the DCDC module to be turned off when its low-level activation pin is suspended, and to control the DCDC main circuit to be turned on when the low-level activation pin is grounded through the vehicle body. The working principle is as follows:

[0032] When the battery system is not configured on the vehicle, the low-level activation pin is suspended and presents a high-impedance state. At this time, the DCDC is in a dormant state, the main circuit is not working, and the control module works to detect the state of the low-level activation pin. If the low-level activation pin continues to be in a high-impedance state, the DCDC is controlled to remain in a dormant state; when the battery system is configured on the vehicle, the low-level activation pin is no longer in a high-impedance state through the vehicle body grounding. At this time, the control module controls the DCDC main circuit to be turned on, and the DCDC converts the high-voltage electricity of the battery pack into low-voltage electricity and supplies power to the vehicle's low-voltage system, thereby realizing the awakening of the DCDC. The battery system is realized to supply power to the low-voltage system immediately after being installed on the vehicle.

[0033] Each DCDC in the battery system is also connected to the battery management system BMS ( Figure 1 The DCDC between battery packs is distinguished by the address code of the battery pack, and the DCDC in the pack is distinguished by the coding pin. When the battery control box detects that the battery pack is low on power, the battery control box sends a shutdown command to the corresponding DCDC through the CAN network, so that the corresponding DCDC is in a completely shut down state, the main circuit does not work, and the control module does not work. At this time, the DCDC consumes almost no power to prevent the battery pack from being seriously low on power. Correspondingly, in this embodiment, the DCDC also includes a high-level activation pin ( Figure 1 The high level activation pin is used to activate the DCDC when the DCDC is completely shut down. The high level activation pin is used to connect the low voltage power of the charger. When the battery system is connected to the charger and enters the charging state, the high level activation pin has a high level to activate the DCDC to put it into working state.

[0034] In this embodiment, an anti-reverse diode is also connected in series on the line that supplies power to the low-voltage system after the DCDC in the battery pack is connected in parallel. The voltage of the DCDC in the battery pack that supplies power to the low-voltage system is lower than the voltage of the DCDC of the vehicle that supplies power to the low-voltage system. When the vehicle is powered on, the power of the voltage system is provided by the DCDC of the vehicle first because the voltage output by the DCDC of the vehicle is high, which can reduce the attenuation of the DCDC in the battery pack and extend the service life of the DCDC in the battery pack.

[0035] Vehicle Example:

[0036] The vehicle of the present invention includes a battery system that realizes low-voltage power supply through DCDC as described in the battery system embodiment of the present invention, and supplies power to the vehicle low-voltage system through the DCDC built into the battery pack of the battery system. The battery system has been described in detail in the battery system embodiment, and will not be repeated in this embodiment.

[0037] In summary, the battery system and vehicle of the present invention that use a DCDC module to supply low-voltage power to the vehicle save the need for setting up necessary protection circuits and structures for the DCDC outside the battery pack by setting the DCDC inside the battery pack, thereby saving vehicle space and reducing vehicle costs. At the same time, each battery pack in the battery system includes a DCDC, and one DCDC outside the battery pack is replaced with multiple DCDCs. When one of them fails, it can still supply power to the low-voltage system of the vehicle, thereby improving the reliability of the low-voltage power supply.

[0038] Furthermore, the present invention detects whether the battery system is installed on the vehicle by detecting whether the low-level activation pin is in a high-impedance state. When the battery system is not installed on the vehicle, the DCDC main circuit is turned off to reduce power damage; after being installed on the vehicle, the DCDC main circuit can be directly turned on to supply power to the vehicle's low-voltage system.

[0039] Furthermore, the DCDC in the battery pack of the present invention is also connected to the vehicle battery management system, which can shut down the DCDC when the battery pack is under-voltage, thereby preventing the DCDC from continuously consuming the battery pack power and aggravating the under-voltage problem.

[0040] Furthermore, the high-level activation pin of the DCDC module of the present invention is used to connect the low-voltage charging circuit or DCDC activation source of the charging gun to enable the DCDC module to start up after receiving a high level, and can automatically start up from a shutdown state when the battery pack is charging.

Claims

1. A battery system for low-voltage power supply of a vehicle through a DCDC module, characterized in that: The i-th battery pack of the battery system is provided with Ni DCDC modules, Ni≥1, i=1,2,……,K, K represents the total number of battery packs; All cells in a battery pack with Ni=1 are connected in series to the high-voltage end of the DCDC module; cells in a battery pack with Ni≥2 are divided into N groups, and cells in one group are connected in series to the high-voltage end of a DCDC module, and cells in different groups are connected to the high-voltage ends of different DCDC modules; The low-voltage ends of the DCDC modules are connected in parallel to output low-voltage electricity to supply power to the vehicle's low-voltage system.

2. The battery system for low-voltage power supply of a vehicle through a DCDC module according to claim 1, characterized in that: The main circuit of each DCDC module is in the on state after the battery system is installed on the vehicle. The low-voltage ends of each DCDC module are connected in parallel and output through the anti-reverse module. The output voltage of the low-voltage ends of the DCDC modules after parallel connection is lower than the voltage of the DCDC output of the whole vehicle, so that the low-voltage system of the vehicle gives priority to using the power output of the DCDC of the whole vehicle when the whole vehicle is powered on.

3. The battery system for low-voltage power supply of a vehicle through a DCDC module according to claim 2, characterized in that: The low-level activation pins of each DCDC module are used to connect to the vehicle body when the battery system is assembled on the vehicle, and are in a floating state when the battery system is not assembled on the vehicle; the DCDC module is used to disconnect the main circuit inside it when its low-level activation pin is in a floating state, and to turn on the main circuit inside it when the low-level activation pin is grounded through the vehicle body to ensure that the main circuits are in a conducting state after the battery system is assembled on the vehicle.

4. The battery system for low-voltage power supply of a vehicle through a DCDC module according to claim 1, characterized in that: The high-level activation pin of each DCDC module is used to connect the low-voltage charging line of the charging gun or the DCDC activation source, so as to start the DCDC module after receiving a high-level signal when the DCDC module is in the shutdown state.

5. The battery system for low-voltage power supply of a vehicle through a DCDC module according to any one of claims 1 to 4, characterized in that: The number of cells in each group in the same battery pack is equal.

6. The battery system for low-voltage power supply of a vehicle through a DCDC module according to any one of claims 1 to 4, characterized in that: The communication pin of the DCDC module is also used to connect to the vehicle battery management system to receive the shutdown command issued by the battery management system and enter the shutdown state when the battery pack is under-voltage.

7. A vehicle that uses a DCDC module to provide low-voltage power to the vehicle, characterized in that: The i-th battery pack of the battery system of the vehicle is provided with Ni DCDC modules, Ni≥1, i=1,2,……,K, K represents the total number of battery packs; All cells in a battery pack with Ni=1 are connected in series to the high-voltage end of the DCDC module; cells in a battery pack with Ni≥2 are divided into N groups, and cells in one group are connected in series to the high-voltage end of a DCDC module, and cells in different groups are connected to the high-voltage ends of different DCDC modules; The low-voltage ends of the DCDC modules are connected in parallel to output low-voltage electricity to supply power to the vehicle's low-voltage system.

8. The vehicle for low-voltage power supply via a DCDC module according to claim 7, characterized in that: The main circuit of each DCDC module is in the on state after the battery system is installed on the vehicle. The low-voltage ends of each DCDC module are connected in parallel and output through the anti-reverse module. The output voltage of the low-voltage ends of the DCDC modules after parallel connection is lower than the voltage of the DCDC output of the whole vehicle, so that the low-voltage system of the vehicle gives priority to using the power output of the DCDC of the whole vehicle when the whole vehicle is powered on.

9. The vehicle for low-voltage power supply via a DCDC module according to claim 8, characterized in that: The low-level activation pins of each DCDC module are used to connect to the vehicle body when the battery system is assembled on the vehicle, and are in a floating state when the battery system is not assembled on the vehicle; the DCDC module is used to disconnect the main circuit inside it when its low-level activation pin is in a floating state, and to turn on the main circuit inside it when the low-level activation pin is grounded through the vehicle body to ensure that the main circuits are in a conducting state after the battery system is assembled on the vehicle.

10. The vehicle for low-voltage power supply via a DCDC module according to claim 7, characterized in that: The high-level activation pin of each DCDC module is used to connect the low-voltage charging line of the charging gun or the DCDC activation source, so as to start the DCDC module after receiving a high-level signal when the DCDC module is in the shutdown state.

11. The vehicle for low-voltage power supply via a DCDC module according to any one of claims 7 to 10, characterized in that: The number of cells in each group in the same battery pack is equal.

12. The vehicle for low-voltage power supply via a DCDC module according to any one of claims 7 to 10, characterized in that: The communication pin of the DCDC module is also used to connect to the vehicle battery management system to receive the shutdown command issued by the battery management system and enter the shutdown state when the battery pack is under-voltage.

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