---
title: 2000_Battery Degradation Platform and Model for Realistic Battery Use Cases
tags:  #機械学習  
author: [小平　大輔](https://convert.docswell.com/user/daisuke-kodaira)
site: [Docswell](https://www.docswell.com/)
thumbnail: https://bcdn.docswell.com/page/V9J23WMDER.jpg?width=480
description: D. Kodaira and S. Han, &quot;Battery Degradation Platform and Model for Realistic Battery Use Cases,&quot; 2020 4th International Conference on Smart Grid and Smart Cities (ICSGSC), 2020, pp. 14-17, doi: 10.1109/ICSGSC50906.2020.9248541.
published: March 31, 22
canonical: https://convert.docswell.com/s/daisuke-kodaira/ZWGVJ5-2022-03-31-093922
---
# Page. 1

![Page Image](https://bcdn.docswell.com/page/V9J23WMDER.jpg)

1
Battery Degradation Platform and Model for
Realistic Battery Use Cases
Daisuke Kodaira
Assistant Professor
Tokyo University of Science, Japan
Tokyo University of Science


# Page. 2

![Page Image](https://bcdn.docswell.com/page/5DEY1LXMJM.jpg)

Problems caused by Photovoltaic(PV) generation
Low Voltage network
High Voltage network
Local Subst
ations
Consumption
Conventional Generation
Long Distance T
ransmission
Local distribution
Present Day Large Desert PV Plants
Tokyo University of Science
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# Page. 3

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Problem in High Voltage network
Local Substations
Without PV
With PV
Demand [MW]
8.5
8
7.5
7
1) Excessive
generation
6.5
2) Demand Rump-up
6
0:00
6:00
12:00
18:00
0:00
Batteries can contribute flat demand profile
… How about the cost?
… How many years is the battery long?
Battery Degradation
Tokyo University of Science
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# Page. 4

![Page Image](https://bcdn.docswell.com/page/GYE91Q5P73.jpg)

State of Health (SOH)
Question.
If we run a battery with the specific profile, how much the battery life will be shortened?
State of Health (SOH) is widely used to evaluate battery life.
𝑆𝑂𝐻[%] =
𝐶𝑟
× 100
𝐶𝑓
𝐶𝑟 : 𝑟𝑒𝑚𝑎𝑖𝑛𝑖𝑛𝑔 𝑒𝑛𝑒𝑟𝑔𝑦 𝐴ℎ 𝑜𝑓𝒖𝒔𝒆𝒅 𝑏𝑎𝑡𝑡𝑒𝑟𝑦 𝑎𝑡 𝑆𝑜𝐶 100%
𝐶𝑓 : 𝑟𝑒𝑚𝑎𝑖𝑛𝑖𝑛𝑔 𝑒𝑛𝑒𝑟𝑔𝑦 𝐴ℎ 𝑜𝑓 𝒇𝒓𝒆𝒔𝒉 𝑏𝑎𝑡𝑡𝑒𝑟𝑦 𝑎𝑡 𝑆𝑜𝐶 100%
𝑆𝑜𝐶 100%
𝑆𝑜𝐶 100%
1000 Cycles….
𝐶𝑓 = 10Ah
𝐶𝑟 = 8Ah
𝑆𝑂𝐻 = 80%
SOH is index of the state comparing with the fresh battery.
We cannot estimate how much the battery gets damaged with various conditions
Tokyo University of Science
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# Page. 5

![Page Image](https://bcdn.docswell.com/page/5GE84GYXJD.jpg)

Factors of battery degradation
We need to build a model to estimate battery degradation.
Mainly 3 conditions are related to degradation.
Oxidation of Electrolyte
Temperature
C-rate
(Current)
Electrolyte Decomposition
Electrode Decomposition
Lithium Plating
Intercalation Gradients
Formation of Li grains
Operating SOC
Current Collector Corrosion
Crystal Structure Disorder
Binder Decomposition
Electrode Decomposition
Tokyo University of Science
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# Page. 6

![Page Image](https://bcdn.docswell.com/page/MLEL6G4NJR.jpg)

SOH Estimation vs Wear Density Function
We proposed Wear Density Function (WDF) [1]
WDF
WDF provides how much a battery ages due to the charge with various conditions
SOH
WDF
Remaining Life
10 Ah
10 Ah
Temperature
25℃
Any degree
Current
10A
Any current
Operating SOC
Always 100% to 0%
Any SOC area
WDF is for evaluating arbitral battery charging profile
[1] S. Han, S. Han, and H. Aki, “A practical battery wear model for electric vehicle charging applica
tions,” Appl. Energy, vol. 113, pp. 1100–1108, Jan. 2014.
Tokyo University of Science
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# Page. 7

![Page Image](https://bcdn.docswell.com/page/54JM5QKQJW.jpg)

Constructing SOH platform based on big data
Example of the Wear Density Function in a discrete manner
Operation
SOC range
100%
100% 𝑡𝑜 90%
ΔEnergy
[Ah]
temp
[℃]
10
20
…
490
500
510
…
990
1000
0%
…
100%
-5
-4
…
25
26
27
…
39
40
60% 𝑡𝑜 50%
Current
[A]
0.1
0.2
…
1.0
1.1
1.2
…
2.9
3.0
𝑊𝑖,1
𝑊𝑖,2
…
𝑊𝑖,500
𝑊𝑖,501
𝑊𝑖,502
…
𝑊𝑖,𝑝−1
𝑊𝑖,𝑝
Δ𝐷𝑒𝑔𝑟𝑎𝑑𝑎𝑡𝑖𝑜𝑛 =
𝑊𝑖 ,1 ∗ 10
+ 𝑊𝑖 ,2 ∗ 20
+
⋮
+ 𝑊𝑖 ,𝑝 ∗ ΔEnergy
0%
Collect from client’s batteries
7
Calculate the degree of degradation
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# Page. 8

![Page Image](https://bcdn.docswell.com/page/ZPJR38XK79.jpg)

Constructing SOH platform based on big data
Operation
SOC range
100%
100% 𝑡𝑜 90%
If we have weight vector 𝑊,
we can estimate proper degradation for
arbitral charging schedules with various conditions
ΔEnergy
[Ah]
temp
[℃]
10
20
…
490
500
510
…
990
1000
0%
…
100%
-5
-4
…
25
26
27
…
39
40
Current
[A]
0.1
0.2
…
1.0
1.1
1.2
…
2.9
3.0
𝑊𝑖,1
𝑊𝑖,2
…
𝑊𝑖,500
𝑊𝑖,501
𝑊𝑖,502
…
𝑊𝑖,𝑝−1
𝑊𝑖,𝑝
Δ𝐷𝑒𝑔𝑟𝑎𝑑𝑎𝑡𝑖𝑜𝑛 =
𝑊𝑖,1 ∗ Δ𝐸𝑛𝑒𝑟𝑔𝑦
+ 𝑊𝑖,2 ∗ Δ𝐸𝑛𝑒𝑟𝑔𝑦
+……
60% 𝑡𝑜 50%
0%
Collect from client’s batteries
8
Calculate the degree of degradation
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# Page. 9

![Page Image](https://bcdn.docswell.com/page/NPEX4865EX.jpg)

Constructing SOH platform based on big data
Gather the conditions information from clients
Operation
SOC range
100%
100% 𝑡𝑜 90%
ΔEnergy
[Ah]
temp
[℃]
10
20
…
490
500
510
…
990
1000
0%
…
100%
-5
-4
…
25
26
27
…
39
40
Current
[A]
0.1
0.2
…
1.0
1.1
1.2
…
2.9
3.0
Measure the damage from
client systems
𝑊𝑖,1
𝑊𝑖,2
…
𝑊𝑖,500
𝑊𝑖,501
𝑊𝑖,502
…
𝑊𝑖,𝑝−1
𝑊𝑖,𝑝
Δ𝐷𝑒𝑔𝑟𝑎𝑑𝑎𝑡𝑖𝑜𝑛 =
𝑊𝑖,1 ∗ Δ𝐸𝑛𝑒𝑟𝑔𝑦
+ 𝑊𝑖,2 ∗ Δ𝐸𝑛𝑒𝑟𝑔𝑦
+……
60% 𝑡𝑜 50%
0%
Calculate W
Collect from client’s batteries
9
Calculate the degree of degradation
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# Page. 10

![Page Image](https://bcdn.docswell.com/page/63EKZK1RED.jpg)

Research Objective
Example of the Wear Density Function matrix
-&gt; Our final goal is calculate 𝑤𝑒𝑖𝑔ℎ𝑡 𝑣𝑒𝑐𝑡𝑜𝑟 𝑥
Estimated battery
degradation based on
another method [2]
(Given data)
Weight vector
(Unknown)
Energy transition
(Given data)
𝑊1,1
Profile No.1
∆𝑞11 ∆𝑞21
∆𝑞31
∆𝑞41
𝑊1,2
Profile No.2
∆𝑞12
∆𝑞22
∆𝑞32
∆𝑞42
𝑊1,3
𝐴
∆𝐷𝑎𝑚𝑎𝑔𝑒
=
∆𝐷𝑎𝑚𝑎𝑔𝑒
𝑊1,4
𝐵
𝑥
𝐴𝑥 = 𝐵
𝑥 = 𝐴−1 𝐵
[2] S. Han, “Apparatus and method for real-time estimation of battery state-of-health”, patent KR101615139B1, 2014
Tokyo University of Science
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# Page. 11

![Page Image](https://bcdn.docswell.com/page/4L73DZQGE5.jpg)

Constructing SOH platform based on big data
• Sending battery management section’s information such as current, temperature, and discharge
amount (∆𝐴ℎ) to a server
• Estimating current Capacity Retention [Ah] in real time based on the battery terminal voltage [1]
• The server estimates WDF function based by accumulated data
Based on the collected data, apply with WDF
to reflect the sensitive deterioration degree
to the app by making deterioration degree
per user’s pattern into big-data
Data transmission
Data transmission
server
Wireless network
Car &amp; application
Analyzing big data
Collecting data such as estimated deterioration degree,
current, voltage, running pattern, temperature, etc.
Estimate deterioration degree by Cycle life
Evaluation Function
*Capacity Retention; The amount of provided energy [Ah] when the battery discharges from SOC 100% to 0%
[1] S. Han, “Apparatus and method for real-time estimation of battery state-of-health”, patent KR101615139B1, 2014
Tokyo University of Science
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# Page. 12

![Page Image](https://bcdn.docswell.com/page/V87DPR9N7G.jpg)

Data example to get WDF
*Capacity Retention; The amount of provided energy [Ah]
when the battery discharges from SOC 100% to 0%
∆𝐸𝑛𝑒𝑟𝑔𝑦
[Ah]
3
5
4
∆𝑞1,2
∆𝑞2,2
∆𝑞3,2
⋮
Initial SOC
[%]
100
75
50
⋮
⋮
⋮
⋮
Final SOC
[%]
75
50
25
⋮
⋮
⋮
⋮
Used energy
Temperature
[C]
40
30
20
⋮
⋮
⋮
⋮
Current
[A]
2.0
1.3
1.6
⋮
⋮
⋮
⋮
Weight
𝑊1
𝑊2
𝑊3
𝑊1
𝑊2
𝑊3
⋮
Condition information
3
∆𝑞1,2
⋮
5
4
𝑊1
∆𝑞2,2
∆𝑞3,2
𝑊2
⋮
𝐴
⋮
𝑊3
𝑥
∆Capacity
Retention [Ah]
0.4
Continuous one
profile from
a user
∆𝐶𝑅2
⋮
Degradation
0.4
=
∆𝐶𝑅2
∆𝐶𝑅3
𝐵
=
𝑥 = 𝐴−1𝐵
Once we calculate 𝑤𝑒𝑖𝑔ℎ𝑡 𝑣𝑒𝑐𝑡𝑜𝑟 𝒙, we can estimate degradation for
arbitral charging/discharging profile with various conditions
Tokyo University of Science
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# Page. 13

![Page Image](https://bcdn.docswell.com/page/4VJPNWZNE8.jpg)

The pseudo experiment data
Distribution of data set (follows normal distribution)
Temperature
Tokyo University of Science
C-rate
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# Page. 14

![Page Image](https://bcdn.docswell.com/page/L2EVK8WY7Q.jpg)

The pseudo experiment data
Initial SOC
Final SOC
∆𝐂𝐚𝐩𝐚𝐜𝐢𝐭𝐲 𝐫𝐞𝐭𝐞𝐧𝐭𝐢𝐨𝐧
Classify all the data set with 3 groups using k-means algorithm
-&gt; Consider 3 conditions!
Tokyo University of Science
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# Page. 15

![Page Image](https://bcdn.docswell.com/page/Z57GQ5DWJL.jpg)

Simulation result to get WDF example
3
∆𝑞1,2
⋮
5
4
𝑊1
∆𝑞2,2
∆𝑞3,2
𝑊2
⋮
⋮
𝐴
0.4
=
∆Energy matrix (k=3)
∆𝐶𝑅3
𝑊3
𝑥
∆𝐶𝑅2
=
∆𝐶𝑅 matrix
𝐵
𝑊1 = 0.465 ∗ 10−4
𝑊2 =0.957 ∗ 10−4
=
inverse
𝑊3 =1.173 ∗ 10−4
We got WDF matrix
as the number of W
Tokyo University of Science
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# Page. 16

![Page Image](https://bcdn.docswell.com/page/V4EQKZ1QEP.jpg)

Thank you
Tokyo University of Science
16
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