Battery device

Abstract

To heat up battery packs that require temperature rise so that power storage ratios of a plurality of battery packs are more equalized.SOLUTION: A controller extracts temperature-rise-required battery packs that require heating up from among a plurality of battery packs, obtains a charge / discharge power amount required for the temperature rise according to an average power storage ratio about each of the temperature-rise-required battery packs, and calculates an integrated charge / discharge power amount. When the integrated charge / discharge power amount is less than a predetermined power amount, the controller controls a corresponding converter so as to heat up the temperature-rise-required battery packs by charging or discharging between the temperature-rise-required battery packs. When the integrated charge / discharge power amount is the predetermined power amount or more, the controller controls the corresponding converter so as to heat up the temperature-rise-required battery packs by charging or discharging between the battery packs obtained by adding at least one of the battery packs that has not been extracted as the temperature-rise-required battery packs from among the plurality of battery packs, to the plurality of temperature-rise-required battery packs.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a battery device, and more particularly to a battery device in which a plurality of battery packs are connected to a power line via a plurality of converters attached to each battery pack. [Background technology]

[0002] A conventional battery device of this type has been proposed that, when the temperature of a plurality of battery packs, each of which has a built-in balancer circuit for equalizing voltage, is below a predetermined temperature, activates the balancer circuit to raise the temperature of the battery packs (see, for example, Patent Document 1). In this device, the lower the temperature of the battery packs, the more battery packs are targeted for charging and discharging, thereby efficiently raising the temperature of the battery packs. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-061719 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-described battery device, when the voltages of the battery packs that require heating are equalized by the balancer circuit, a voltage difference occurs between the voltage of the heated battery pack and the voltage of the battery pack that does not require heating.

[0005] The battery device of the present disclosure has a primary object to raise the temperature of battery packs that require heating so as to more evenly distribute the charge storage ratios of the plurality of battery packs. [Means for solving the problem]

[0006] The battery device of the present disclosure employs the following measures to achieve the above-mentioned main object.

[0007] The battery device of the present disclosure comprises: A plurality of battery packs; a plurality of converters attached to each of the plurality of battery packs; a power line connected to the plurality of battery packs via the plurality of converters; a control device for controlling the plurality of converters; A battery device comprising: the control device extracts a plurality of battery packs that require a temperature increase from the plurality of battery packs, determines charge / discharge power required to increase the temperature of the plurality of battery packs according to an average power storage rate of the plurality of battery packs, and calculates an integrated charge / discharge power that is an integrated value of the charge / discharge power, and controls the plurality of converters to increase the temperature of the plurality of battery packs that require a temperature increase by charging / discharging between the plurality of battery packs that require a temperature increase when the integrated charge / discharge power is less than a predetermined power, and controls the plurality of converters to increase the temperature of the plurality of battery packs that require a temperature increase by adding at least one of the battery packs that has not been extracted as the plurality of battery packs that require a temperature increase to the plurality of battery packs that require a temperature increase when the integrated charge / discharge power is equal to or greater than the predetermined power. It is characterized by:

[0008] In the battery device disclosed herein, multiple battery packs that require warm-up are selected from multiple battery packs, and the charge / discharge power required to warm up the multiple battery packs is calculated based on the average power storage ratio of the multiple battery packs, and the integrated charge / discharge power is calculated. When the integrated charge / discharge power is less than a predetermined power, each converter is controlled to warm up the multiple battery packs that require warm-up by charging / discharging between the multiple battery packs. On the other hand, when the integrated charge / discharge power is equal to or greater than the predetermined power, each converter is controlled to warm up the multiple battery packs that require warm-up by charging / discharging between the multiple battery packs, adding at least one battery pack not selected as a battery pack that requires warm-up to the multiple battery packs that require warm-up. This allows the power storage ratio of the warmed battery packs among the multiple battery packs to be closer to the average power storage ratio. As a result, the battery packs that require warm-up can be heated so that the power storage ratios of the multiple battery packs are more equalized. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing an outline of the configuration of a battery device 20 according to an embodiment of the present disclosure. [Figure 2] 4 is a flowchart showing an example of a temperature increase process executed by an electronic control unit 30. [Figure 3] FIG. 10 is an explanatory diagram showing an example of the state of the temperature increase process for ten battery packs. DETAILED DESCRIPTION OF THE INVENTION

[0010] Next, a mode (embodiment) for carrying out the present disclosure will be described. Fig. 1 is a configuration diagram showing an outline of the configuration of a battery device 20 according to one embodiment of the present disclosure. As shown in the figure, the battery device 20 of the embodiment includes a plurality of battery packs 22a-22n, a plurality of DC / DC converters 24a-24n connected to the terminals of the plurality of battery packs 22a-22n via individual battery power lines 23a-23n, and an electronic control unit 30.

[0011] Each battery pack 22a-22n has the same configuration, and is configured, for example, by connecting multiple lithium-ion battery cells in series. A relay (not shown) is attached to each individual battery power line 23a-23n connected to the terminal of each battery pack 22a-22n to disconnect each battery pack 22a-22n.

[0012] Each of the DC / DC converters 24a-24n is configured as the same well-known DC / DC converter and is connected to a shared power line 40. A plurality of capacitors 25a-25n are attached to the positive and negative lines of the shared power line 40. The plurality of capacitors 25a-25n have the same capacitance. When a drive device or the like is connected to a terminal 42 of the shared power line 40, the battery device 20 can supply power to the drive device or the like.

[0013] The electronic control unit 30 is configured as a microcomputer centered on a CPU (not shown), and receives as inputs charge / discharge currents Ia-In detected by multiple current sensors 26a-26n attached to individual battery power lines 23a-23n connected to each battery pack 22a-22n, battery voltages Va-Vn detected by multiple voltage sensors 27a-27n attached to the individual battery power lines 23a-23n, and battery temperatures Ta-Tn detected by multiple temperature sensors 28a-28n attached to each battery pack 22a-22n. The electronic control unit 30 outputs drive control signals to each of the DC / DC converters 24a-24n. When not charging or discharging, the electronic control unit 30 determines the charge storage ratios SOCa to SOCn of each battery pack 22a to 22n based on the open circuit voltages OCV detected by each voltage sensor 27a to 27n, and when charging or discharging, calculates the charge storage ratios SOCa to SOCn of each battery pack 22a to 22n based on the integrated values ​​of the charge and discharge currents Ia to In detected by each current sensor 26a to 26n.

[0014] Next, the operation of the battery device 20 of this embodiment configured as above, particularly the operation when warming up the battery packs 22a to 22n when cold, will be described. Figure 2 is a flowchart showing an example of a warming process executed by the electronic control unit 30.

[0015] When the temperature increase process is executed, the electronic control unit 30 first selects a battery pack that needs to be heated from among the plurality of battery packs 22a-22n (step S100). This selection can be performed by determining the battery pack whose battery temperature Ta-Tn detected by the plurality of temperature sensors 28a-28n attached to each battery pack 22a-22n is less than a threshold value Tref as the battery pack that needs to be heated. The threshold value Tref can be the lower limit temperature of the temperature range in which the battery pack functions satisfactorily or a temperature close to that limit.

[0016] Next, an average power storage ratio SOCav is calculated as an average value of the power storage ratios SOCa to SOCn of the plurality of battery packs 22a to 22n (step S110). The power storage ratios SOCa to SOCn of the plurality of battery packs 22a to 22n may be calculated based on the open circuit voltages OCV of the respective battery packs 22a to 22n detected by the respective voltage sensors 27a to 27n.

[0017] Next, the charge / discharge power Pchg required to heat each battery pack requiring warm-up is calculated (step S120). The charge / discharge power Pchg required to heat the battery pack requiring warm-up can be calculated as the charge power required to raise the battery pack temperature to the target temperature for battery packs whose power storage rate SOC of the battery pack requiring warm-up is smaller than the average power storage rate SOCav, and as the discharge power required to raise the battery pack temperature to the target temperature for battery packs whose power storage rate SOC of the battery pack requiring warm-up is greater than the average power storage rate SOCav. For battery packs whose power storage rate SOC of the battery pack requiring warm-up is the same as the average power storage rate SOCav, the charge / discharge power Pchg is calculated as the charge power or the discharge power so that the integrated value ΣPchg of the charge / discharge power Pchg, which will be described later, is small.

[0018] The charge / discharge power Pchg required to heat up the battery packs requiring warm-up is then integrated to calculate an integrated value ΣPchg (step S130), and it is determined whether the absolute value of the integrated value ΣPchg is equal to or greater than a threshold Pref (step S140). The threshold Pref is set so that the power storage ratio SOC of the discharge-side battery packs requiring warm-up and the charge-side battery packs requiring warm-up after warm-up does not deviate too much from the average power storage ratio SOCav, and is preferably determined according to the total number of battery packs.

[0019] If it is determined in step S140 that the absolute value of the integrated value ΣPchg is less than the threshold value Pref, a value for offsetting the discharge power of the discharge-side battery pack requiring warm-up and the charge power of the charge-side battery pack requiring warm-up is calculated based on the integrated value ΣPchg (step S160). The offset is performed so that the integrated value ΣPchg becomes zero, that is, so that the integrated value of the discharge power of the discharge-side battery pack requiring warm-up matches the integrated value of the charge power of the charge-side battery pack requiring warm-up. FIG. 3 is an explanatory diagram showing an example of the warm-up process for 10 battery packs. In this example, battery packs No. 1 to No. 3 are selected as battery packs requiring warm-up. Of battery packs No. 1 to No. 3, with an average power storage rate SOCav of 50%, battery pack No. 1 is the charge side, battery pack No. 2 is the charge side (either the charge side or the discharge side), and battery pack No. 3 is the discharge side. The charge / discharge power Pchg of battery packs No. 1 to No. 3 to reach the target temperature are -15 kW, -15 kW, and 20 kW, and the integrated value Pchg is -10 kW. To set this integrated value Pcgh to 0, the provisional allocations of battery packs No. 1 to No. 3 are -15 kW, -15 kW, and 30 kW, and the offsets of battery packs No. 1 to No. 3 to set the integrated value ΣPcgh to 0 are all 3.333 kW. The charge / discharge power Pchg of battery packs No. 1 to No. 3 during the executed temperature rise are -11.777 kW (-15 + 3.333 = -11.777), -11.777 kW (-15 + 3.333 = -11.777), and 23.333 kW (20 + 3.333 = 23.333).

[0020] The temperature of the battery pack requiring warm-up is then increased using the charge / discharge power Pchg after the offset (step S170), and this process ends. The temperature increase can be achieved by controlling the corresponding DC / DC converter so that the discharge power of the battery pack requiring warm-up on the discharge side becomes the discharge power after the offset, and by controlling the corresponding DC / DC converter so that the charge power of the battery pack requiring warm-up on the charge side becomes the charge power after the offset.

[0021] If it is determined in step S140 that the absolute value of the integrated value ΣPchg is equal to or greater than the threshold value Pref, an additional battery pack having a lower temperature is selected as a battery pack requiring warm-up from among the plurality of battery packs 22a-22n that has not been selected as a battery pack requiring warm-up, so that the absolute value of the integrated value ΣPchg of the charge / discharge power Pchg required to warm up the battery pack selected as the battery pack requiring warm-up is less than the threshold value Pref (step S150). Then, the integrated value ΣPchg of the charge / discharge power Pchg of the battery packs requiring warm-up including the added battery pack is used to determine a value for offsetting the discharge power of the discharge-side battery pack requiring warm-up and the charge power of the charge-side battery pack requiring warm-up (step S160), and the offset charge / discharge power Pchg is used to heat up the battery pack requiring warm-up (step S170), after which the process ends.

[0022] In the battery device 20 of the embodiment described above, a warm-up-required battery pack that needs to be warmed up is selected from the plurality of battery packs 22a-22n, and the charge / discharge power Pchg required to warm up the plurality of warm-up-required battery packs is calculated according to the average power storage rate SOCav of the plurality of battery packs 22a-22n and the target temperature, and an integrated value ΣPchg of the charge / discharge power Pchg is calculated. Then, when the absolute value of the integrated value ΣPchg is less than a threshold value Pref, an offset value is calculated between the discharge power of the discharge-side warm-up-required battery pack and the charge power of the charge-side warm-up-required battery pack according to the integrated value ΣPchg, and the temperature of the warm-up-required battery pack is raised using the offset charge / discharge power Pchg. On the other hand, when the absolute value of the integrated value ΣPchg is equal to or greater than the threshold Pref, a battery pack having a lower temperature is selected as a battery pack requiring warm-up from among the battery packs 22a-22n that have not been selected as a battery pack requiring warm-up so that the absolute value of the integrated value ΣPchg is less than the threshold Pref. The integrated value ΣPchg of the charge / discharge power Pchg of the battery packs requiring warm-up, including the added battery pack, is used to determine a value for offsetting the charge / discharge power Pchg. The offset charge / discharge power Pchg is used to warm up the battery pack requiring warm-up. This allows the power storage ratio SOC of the battery pack that has been warmed up among the battery packs 22a-22n to be closer to the average power storage ratio SOCsv. As a result, the battery pack requiring warm-up can be heated so that the power storage ratios SOC of the battery packs 22a-22n are more uniform.

[0023] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problems" section will be described below. In the embodiment, the plurality of battery packs 22a-22n correspond to the "plurality of battery packs," the plurality of DC / DC converters 24a-24n correspond to the "plurality of converters," the shared power line 40 corresponds to the "power line," and the electronic control unit 30 corresponds to the "control device."

[0024] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0025] The present disclosure has been described above using embodiments, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be embodied in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0026] The present disclosure is applicable to the battery device 20 manufacturing industry and the like. [Explanation of symbols]

[0027] 20 battery device, 22a to 22n battery pack, 23a to 23n individual battery power line, 24a to 24n DC / DC converter, 25a to 25n capacitor, 26a to 26n current sensor, 27a to 27n voltage sensor, 28a to 28n temperature sensor, 30 electronic control unit, 40 shared power line, 42 terminal.

Claims

[Claim 1] A plurality of battery packs; a plurality of converters attached to each of the plurality of battery packs; a power line connected to the plurality of battery packs via the plurality of converters; a control device for controlling the plurality of converters; A battery device comprising: the control device extracts a plurality of battery packs that require heating from the plurality of battery packs, determines charge / discharge power required to heat the plurality of battery packs that require heating according to an average power storage rate of the plurality of battery packs, calculates an integrated charge / discharge power that is an integrated value of the charge / discharge power, and controls the plurality of converters to heat the plurality of battery packs that require heating by charging / discharging between the plurality of battery packs that require heating when the integrated charge / discharge power is less than a predetermined power, and controls the plurality of converters to heat the plurality of battery packs that require heating by adding at least one of the battery packs that has not been extracted as the plurality of battery packs that require heating to the plurality of battery packs that require heating. A battery device characterized by:

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